Reduviidae is the largest family of predaceous land Hemiptera, containing about 6250 species and subspecies in 913 genera and 25 subfamilies (Maldonado, 1990). Reduviids are abundant, they occur worldwide and they are voracious predators. Hence, they are referred to as  “assassin bugs”. Being larger than many other predaceous land bugs and encampasing in their development a greater range of size, assassin bugs consume not only more prey but also a wider array of prey. Because they are polyphagous, assassin bugs may not useful as predators on specific pests but they are valuable predators in situations where a variety of insect pests occur. Moreover, they kill more prey than they need to satiate themselves. Thus, assassin bugs are important mortality factors and should be conserved and augmented for their utilization in biocontrol programmes (Ambrose, 1987; 1988; 1991; 1996; 1999; 2000; Schaefer, 1988; Schaefer and Ahmad, 1987).

 

Conservation of assassin bugs can be achieved only if their biosystematics and bioecology are studied thoroughly. One must know not only the insect is, but also what its relatives and what its phylogenetic relationships are; such knowledge broadens and deepens the biological information and thereby makes it more useful (Schaefer, 1988).

Despite the abundance of world’s reduviid fauna and its rich taxonomic, geographic, ecological, trophic, morphological, biological and behaviour diversity and despite its prey record and biocontrol potential (Ambrose, 1996a,b; 1999, 2000), studies on reduviids are meagre. It is interesting to report here that what we know on assassin bugs is almost  what we know on Oriental assassin bugs.

 

The author has been studying the bioecology, ecophysiology, ethology and biocontrol potential of Oriental assassin bugs, since 1976. His continued research yielded abundant information on the distribution and diversity of 370 species of assassin bugs  recorded from Indian faunal limits (personal observation since 1976, Ambrose, 1999, 2000;  Murugan, 1988; Ravichandran, 1988; examinations of reduviid collections of Prof. Carl W.Schafer, University of Connecticut, USA in 1997 and 1999, examination of museum specimens at Smithsonian Institute, Washington D.C., USA and Natural History Museum, London, UK in 1999). The information on distribution and diversity  are discussed under the following headings: 1. taxonomical diversity 2. ecological diversity 3. structural diversity and 4. behavioural and biological diversity. This chapter attempts  to give a holistic approach for better understanding of interaction on taxonomical, ecological, structural and behavioural and biological diversity of assassin bugs.

 

TAXONOMICAL DIVERSITY

 

The family Reduviidae contains more subfamilies than any other hemipteran family and their composition and relationship remains unsettled (Ambrose, 1999, 2000). Hence, there is an absolute need for a complete comprehensive reassessment of the family higher level classification and phylogenetic relationships.

 

Distant (1902 and 1910) in his Fauna of British India, described 342 species of reduviids belonging to 106 genera and 13 subfamilies including Nabidae and treating Ectinoderinae under Ectrichodiinae, Physoderinae under Peiratinae and Centrocneminae, Reduviinae and Triatominae together as Acanthaspidinae. In this chapter, fifteen subfamilies with 106 genera and 370 species from Indian faunal limits are given (Maldonado, 1990) (table 1).

 

Harpactorinae is the most dominant (37%) reduviid fauna with 136 species under 34 genera Among harpactorines, Coranus and Sphedanolestes (17 species, each) dominated followed by Rhynocoris (13 species), Sycanus (12 species), Endochus (11 species)  and Rhaphidosoma (six species), Euagoras and Macracanthopsis (five species, each),  Alcemna, Epidaus and Irantha (four species, each), Biasticus and Brassivola, Isyndus, and Platerus  (3 species, each), Cosmolestes, Cydnocoris, Lanca, Ploididus, Rhirbus, Velinus, Vesbius and Villanovanus (two species, each) and the rermaining 10 genera are represented by one species, each.

 

The next abundant subfamily is Reduviinae with 61 species under 14 genera. Interestingly, 40 species (66%) belong to a single genus Acanthaspis. It is followed by Edocla with 5 species, Empyrocoris, Pasira, Reduvius and Velitra are represented by two species, each. All the other eight genera are represented by one species, each.

 

Peiratinae follows Reduviinae in its abundance. It comprises of 44 species under nine genera. Interestingly, as observed for Reduviinae, the major constituents of Peiratinae too are from a single genus Ectomocoris (55%). It is followed by Peirates (20%). Except Cleptocoris, Lestomerus, Phalantus and Sirthenea (two species, each) all the other remaining three genera are represented by one species, each.

 

Stenopodainae very closely follows Peiratinae with 38 species under 11 genera. Here as observed for Reduviinae and Peiratinae, a single genus Oncocephalus holds the major constitutuents (55%). Two genera Canthesancus and Pygolampis have three species, each followed by Aulacogenia, Caunus, Sastrapada, two species, each. The remaining genera are represented by one species, each.

 

Ectrichodiinae very closely follows Stenopodainae with 34 species under 10 genera. The most abundant genera are Haematorrhophus and Ectrychotes(11 species, each). Except Labidocoris and Scadra (three species, each) the remaining six genera are represented by lone species, each.

 

Emesinae has 19 species under eleven genera. Ploiaria is the most abundnat genus  (four species) followed by Bagauda, Emesopsis, Ghilianella and Myiophanes (two species, each). All other six genera have one species, each.

 

Salyavatinae has 11 species under five genera. Unlike Reduviinae, Peiratinae and Stenopodainae, the distribution of species under five genera is not polarized. Lisarda, Petalocheirus and Paralisarda possess three species, each and  Nudiscutella and Valentina only one species, each.

 

Triatominae has six species. Here again five species are polarized in a single genus Linshcosteus and one species in Triatoma.

Remarkably out of the seven saicines six are coming under a genus Polytoxus. Similarly out of the five species of Tribelocephalinae, three belong to one genus Tribelocephala and all two holoptilines are under the genus Holoptilus.

 

In Centrocneminae too, out of the four species, three belong to Paracentrocnemis. Subfamilies Apiomerinae, Ectinoderinae and  Physoderinae  are represented by lone species, each. Distant described four species and three genera under Apiomerinae and added that, few species of Neotropical apiomerines are found in Tropical and Ethiopian regions. But it is interesting as well as intriguing that except the lone specimen (Ectinoderus sp.) present in the collection of Prof. Carl W. Schaefer (at present donated to me), my 25 years, field study could not yield a single apiomerine thereby suggesting its rarity or possible extinction in the tropical region.

 

ECOLOGICAL DIVERSITY

 

Ecological diversity of assassin bugs is discussed under two subheadings: 1. microhabitat and 2. habitat.

 

Microhabitat

 

Assassin bugs have been recorded from four major microhabitats viz., under boulders, on shrubs, under the bark and in litter (table 2).

Analysis of data reveals that distribution and diversity of assassin bugs  in relation to their microhabitats are well pronounced. For instance, out of the known  microhabitats of 238 species, 82 species of assassin bugs  (34%) live exclusively under boulders, 30 species (13%) on shrubs, 14 under the bark (6%) and 8 in litter (3%). The species which are exclusively present in a particular microhabitat are considered to be endemic to the microhabitat. Endemism under boulders is more predominant followed by under the bark and in litter. Many species dwell more than in one microhabitat. For instance, 26 species (11%) dwell  under boulders and in litter, 17 species in aerial and on shrubs (7%), six species, each under boulders and in crevices and under bark and litter (3%) and five species in shrubs and in litter (2%). Some species are recorded from even up to four different microhabitats at different occasions. The microhabitats of 101 species are not known.

 

Microhabitats of apiomerines, ectinoderines and physoderines are not known. The known microhabitats of the centrocnemines are  under boulders and in litter.

 

Ectrichodiines live only in concealed microhabitats. Out of the 34 ectrichodiines recorded, the majority of them (56%) live under boulders and thereafter under bark. Some species occupy more than one microhabitat. Interestingly, all the Haematorrhophus, Scadra and Stegius species recorded, live only under boulders. This might be due to their larger size which could not to be concealed under bark nor in the litter and due to the availability of millipedes under boulders, their known prey.

Microhabitat of only 12 emesines is known. They are predominantly found underneath boulders and on vegetations. One emesine S.susainathani was collected from termitarium. Empicoris, Ischnobaena, Ischnobaenella and Myophanes species are found on vegetations and Ploiaria species only under boulders except P.nude which is also found on bark.

 

Among the 136 species of harpactorines recorded, the majority of them are on shrubs. They occupy a variety of microhabitats such as underneath bark, in litter, under boulders and in termitarium. Alcemna, Brassivola, Cydnocoris, Endochus, Euagoras, Irantha, Lanca, Macracanthopsis, Neonagausta, Neovillanovanus, Sphedanolestes and Vesbius species are found either in flying or alighting on shrubs. Coranus species are found either in litter or underneath boulders, except two species which are also found on shrubs. Sycanus species are generally found on shrubs or under barks and rarely in litter. Members of Rhaphidosoma, Platerus and Rhynocoris are found underneath boulders, in litters and on shrubs. R.atkinsoni is also recorded in termitarium.

 

The known microhabitats for holoptilines are under boulders and in litter.

Peiratines generally live under boulders (41%) and some of them are also recorded in adjacent litter. E.horridus and P.affinis are also found under bark.

 

As observed for peiratines,  reduviines generally live under boulders (43%) followed by in bark (13%). Many bark dwelling reduviines are recorded especially in the genus Acanthaspis. Edocla, Mesacanthaspis, Neoacanthaspis, Pasira, Pasiropsis and Paralenaeus are found only under boulders and some members also occupy nearby litter. Members of Sminthocoris and Velitra are dwellers of  either under bark or in litter.

 

Members of Saicinae are recorded on shrubs (43%), in litter (14%) and both on shrubs and in litter (14%).

 

Salyavatines are predominantly litter dwellers followed by living under boulders. Lisarda species are found underneath boulders and in litter whereas Nudiscutella species live only underneath boulders and Paralisarda species live only in litter.

 

Triatomines prefer crevices. Linshcosteus species are collected from crevices of boulders whereaReduviidae is the largest family of predaceous land Hemiptera, containing about 6250 species and subspecies in 913 genera and 25 subfamilies (Maldonado, 1990). Reduviids are abundant, they occur worldwide and they are voracious predators. Hence, they are referred to as  “assassin bugs”. Being larger than many other predaceous land bugs and encampasing in their development a greater range of size, assassin bugs consume not only more prey but also a wider array of prey. Because they are polyphagous, assassin bugs may not useful as predators on specific pests but they are valuable predators in situations where a variety of insect pests occur. Moreover, they kill more prey than they need to satiate themselves. Thus, assassin bugs are important mortality factors and should be conserved and augmented for their utilization in biocontrol programmes (Ambrose, 1987; 1988; 1991; 1996; 1999; 2000; Schaefer, 1988; Schaefer and Ahmad, 1987).

 

Conservation of assassin bugs can be achieved only if their biosystematics and bioecology are studied thoroughly. One must know not only the insect is, but also what its relatives and what its phylogenetic relationships are; such knowledge broadens and deepens the biological information and thereby makes it more useful (Schaefer, 1988).

 

Despite the abundance of world’s reduviid fauna and its rich taxonomic, geographic, ecological, trophic, morphological, biological and behaviour diversity and despite its prey record and biocontrol potential (Ambrose, 1996a,b; 1999, 2000), studies on reduviids are meagre. It is interesting to report here that what we know on assassin bugs is almost  what we know on Oriental assassin bugs.

 

The author has been studying the bioecology, ecophysiology, ethology and biocontrol potential of Oriental assassin bugs, since 1976. His continued research yielded abundant information on the distribution and diversity of 370 species of assassin bugs  recorded from Indian faunal limits (personal observation since 1976, Ambrose, 1999, 2000;  Murugan, 1988; Ravichandran, 1988; examinations of reduviid collections of Prof. Carl W.Schafer, University of Connecticut, USA in 1997 and 1999, examination of museum specimens at Smithsonian Institute, Washington D.C., USA and Natural History Museum, London, UK in 1999). The information on distribution and diversity  are discussed under the following headings: 1. taxonomical diversity 2. ecological diversity 3. structural diversity and 4. behavioural and biological diversity. This chapter attempts  to give a holistic approach for better understanding of interaction on taxonomical, ecological, structural and behavioural and biological diversity of assassin bugs.

 

TAXONOMICAL DIVERSITY

 

The family Reduviidae contains more subfamilies than any other hemipteran family and their composition and relationship remains unsettled (Ambrose, 1999, 2000). Hence, there is an absolute need for a complete comprehensive reassessment of the family higher level classification and phylogenetic relationships.

 

Distant (1902 and 1910) in his Fauna of British India, described 342 species of reduviids belonging to 106 genera and 13 subfamilies including Nabidae and treating Ectinoderinae under Ectrichodiinae, Physoderinae under Peiratinae and Centrocneminae, Reduviinae and Triatominae together as Acanthaspidinae. In this chapter, fifteen subfamilies with 106 genera and 370 species from Indian faunal limits are given (Maldonado, 1990) (table 1).

 

Harpactorinae is the most dominant (37%) reduviid fauna with 136 species under 34 genera Among harpactorines, Coranus and Sphedanolestes (17 species, each) dominated followed by Rhynocoris (13 species), Sycanus (12 species), Endochus (11 species)  and Rhaphidosoma (six species), Euagoras and Macracanthopsis (five species, each),  Alcemna, Epidaus and Irantha (four species, each), Biasticus and Brassivola, Isyndus, and Platerus  (3 species, each), Cosmolestes, Cydnocoris, Lanca, Ploididus, Rhirbus, Velinus, Vesbius and Villanovanus (two species, each) and the rermaining 10 genera are represented by one species, each.

 

The next abundant subfamily is Reduviinae with 61 species under 14 genera. Interestingly, 40 species (66%) belong to a single genus Acanthaspis. It is followed by Edocla with 5 species, Empyrocoris, Pasira, Reduvius and Velitra are represented by two species, each. All the other eight genera are represented by one species, each.

 

Peiratinae follows Reduviinae in its abundance. It comprises of 44 species under nine genera. Interestingly, as observed for Reduviinae, the major constituents of Peiratinae too are from a single genus Ectomocoris (55%). It is followed by Peirates (20%). Except Cleptocoris, Lestomerus, Phalantus and Sirthenea (two species, each) all the other remaining three genera are represented by one species, each.

 

Stenopodainae very closely follows Peiratinae with 38 species under 11 genera. Here as observed for Reduviinae and Peiratinae, a single genus Oncocephalus holds the major constitutuents (55%). Two genera Canthesancus and Pygolampis have three species, each followed by Aulacogenia, Caunus, Sastrapada, two species, each. The remaining genera are represented by one species, each.

 

Ectrichodiinae very closely follows Stenopodainae with 34 species under 10 genera. The most abundant genera are Haematorrhophus and Ectrychotes(11 species, each). Except Labidocoris and Scadra (three species, each) the remaining six genera are represented by lone species, each.

 

Emesinae has 19 species under eleven genera. Ploiaria is the most abundnat genus  (four species) followed by Bagauda, Emesopsis, Ghilianella and Myiophanes (two species, each). All other six genera have one species, each.

 

Salyavatinae has 11 species under five genera. Unlike Reduviinae, Peiratinae and Stenopodainae, the distribution of species under five genera is not polarized. Lisarda, Petalocheirus and Paralisarda possess three species, each and  Nudiscutella and Valentina only one species, each.

 

Triatominae has six species. Here again five species are polarized in a single genus Linshcosteus and one species in Triatoma.

Remarkably out of the seven saicines six are coming under a genus Polytoxus. Similarly out of the five species of Tribelocephalinae, three belong to one genus Tribelocephala and all two holoptilines are under the genus Holoptilus.

 

In Centrocneminae too, out of the four species, three belong to Paracentrocnemis. Subfamilies Apiomerinae, Ectinoderinae and  Physoderinae  are represented by lone species, each. Distant described four species and three genera under Apiomerinae and added that, few species of Neotropical apiomerines are found in Tropical and Ethiopian regions. But it is interesting as well as intriguing that except the lone specimen (Ectinoderus sp.) present in the collection of Prof. Carl W. Schaefer (at present donated to me), my 25 years, field study could not yield a single apiomerine thereby suggesting its rarity or possible extinction in the tropical region.

 

ECOLOGICAL DIVERSITY

 

Ecological diversity of assassin bugs is discussed under two subheadings: 1. microhabitat and 2. habitat.

 

Microhabitat

 

Assassin bugs have been recorded from four major microhabitats viz., under boulders, on shrubs, under the bark and in litter (table 2)..

Analysis of data reveals that distribution and diversity of assassin bugs  in relation to their microhabitats are well pronounced. For instance, out of the known  microhabitats of 238 species, 82 species of assassin bugs  (34%) live exclusively under boulders, 30 species (13%) on shrubs, 14 under the bark (6%) and 8 in litter (3%). The species which are exclusively present in a particular microhabitat are considered to be endemic to the microhabitat. Endemism under boulders is more predominant followed by under the bark and in litter. Many species dwell more than in one microhabitat. For instance, 26 species (11%) dwell  under boulders and in litter, 17 species in aerial and on shrubs (7%), six species, each under boulders and in crevices and under bark and litter (3%) and five species in shrubs and in litter (2%). Some species are recorded from even up to four different microhabitats at different occasions. The microhabitats of 101 species are not known.

 

Microhabitats of apiomerines, ectinoderines and physoderines are not known. The known microhabitats of the centrocnemines are  under boulders and in litter.

 

Ectrichodiines live only in concealed microhabitats. Out of the 34 ectrichodiines recorded, the majority of them (56%) live under boulders and thereafter under bark. Some species occupy more than one microhabitat. Interestingly, all the Haematorrhophus, Scadra and Stegius species recorded, live only under boulders. This might be due to their larger size which could not to be concealed under bark nor in the litter and due to the availability of millipedes under boulders, their known prey.

 

Microhabitat of only 12 emesines is known. They are predominantly found underneath boulders and on vegetations. One emesine S.susainathani was collected from termitarium. Empicoris, Ischnobaena, Ischnobaenella and Myophanes species are found on vegetations and Ploiaria species only under boulders except P.nude which is also found on bark.

 

Among the 136 species of harpactorines recorded, the majority of them are on shrubs. They occupy a variety of microhabitats such as underneath bark, in litter, under boulders and in termitarium. Alcemna, Brassivola, Cydnocoris, Endochus, Euagoras, Irantha, Lanca, Macracanthopsis, Neonagausta, Neovillanovanus, Sphedanolestes and Vesbius species are found either in flying or alighting on shrubs. Coranus species are found either in litter or underneath boulders, except two species which are also found on shrubs. Sycanus species are generally found on shrubs or under barks and rarely in litter. Members of Rhaphidosoma, Platerus and Rhynocoris are found underneath boulders, in litters and on shrubs. R.atkinsoni is also recorded in termitarium.

 

The known microhabitats for holoptilines are under boulders and in litter.

 

Peiratines generally live under boulders (41%) and some of them are also recorded in adjacent litter. E.horridus and P.affinis are also found under bark.

 

As observed for peiratines,  reduviines generally live under boulders (43%) followed by in bark (13%). Many bark dwelling reduviines are recorded especially in the genus Acanthaspis. Edocla, Mesacanthaspis, Neoacanthaspis, Pasira, Pasiropsis and Paralenaeus are found only under boulders and some members also occupy nearby litter. Members of Sminthocoris and Velitra are dwellers of  either under bark or in litter.

 

Members of Saicinae are recorded on shrubs (43%), in litter (14%) and both on shrubs and in litter (14%).

 

Salyavatines are predominantly litter dwellers followed by living under boulders. Lisarda species are found underneath boulders and in litter whereas Nudiscutella species live only underneath boulders and Paralisarda species live only in litter.

 

Triatomines prefer crevices. Linshcosteus species are collected from crevices of boulders whereas Triatoma from crevices of human inhabitations.

 

Tribelocephalines live underneath boulders and very rarely in litter accumulated adjacent to the boulders (table 2, fig. 1).

 

Habitat

 

The habitat diversity of assassin bugs is discussed with special reference to the three major ecosystems viz., tropical rainforest, semiarid zone and scrub jungle (table 2 and fig. 2).

 

 

Habitats of 303 reduviids are known. Among them one hundred and eight reduviids (36%) exclusively dwell in tropical rainforest, 26 species in the semiarid zone (9%) and 24 species in scrub jungle (8%) ecosystems. Many species are found in all the three major ecosystems (19 species, 6%) as well as in adjacent agroecosystems. Based on the habitat of known species of assassin bugs  one can understand that they are more common in tropical rainforests than in semiarid zones and scrub jungles. Assassin bugs endemic to tropical rainforests are greater in number than to semiarid zones and scrub jungles. It is emphasized, that many assassin bugs which are found in diverse habitats are also found in the adjacent agroecosystems. Many reduviids  also share  more than one major ecosystem. For instance, 23 species share semiarid zones and scrub jungles, 19 species share scrub jungles and tropical rainforests and seven species share semiarid zones and tropical rainforests. Two triatomines are exclusively present in human dwellings. Twelve  species were found attracted to light and two of them also found in agroecosystems. However, their actual habitat is not known.

 

Habitat of members of Apiomerinae, Ectinoderinae and Physoderinae were not recorded. The known habitat of one centrocnemine is scrub jungle and tropical rainforest.

 

Seven ectrichodiines are exclusively present in tropical rainforests. Five species are found in both semiarid zones and scrub jungles. Similarly another six species are found in scrub jungles and tropical rainforests. Four species, E.pilicornis, H.nigroviolaceous, L.elegans and S.annulipes are found in all the three ecosystems. Two species E.abbreviatus and H.fovealis are recorded from agroecosystem. Ectrichodiines are diurnal.

 

Except Ploiara species, all other emesines are recorded from tropical rainforest ecosystem or adjacent agroecosystems or as light attracted predators.

 

Sixty one  harpactorines (45%) live only in the rainforests and eight species each in semiarid zone and scrub jungle ecosystems. Alcemna, Biasticus, Brassivola, Cydnocoris, Endochus, Epidaus, Euagoras, Irantha, Macracanthospis, Neonagusta, Neovillanovanus, Occamus, Panthous, Rhirbus, Serendiba, Sphedanolestes, Sycanus, and Vesbius species are found only in the tropical rainforests and are rarely seen in adjacent scrub jungles, generally at higher altitudes where tropical rainforest conditions prevail or adjacent semiarid zones or agroecosystems.

C.atricapilus, C.spiniscutis, C.vitellinus, R.longifrons are found in scrub jungles, semiarid zones and adjacent agroecosystems. P.brevispina and S.signatus are seen in tropical rainforests, adjacent scrub jungles and agroecosystems. Many harpactorines found in the scrub jungles, semiarid zones and agroecosystems are also present in the aprons of localized tropical rainforests during summer when scrub jungle conditions prevail. L.guerini is present in scrub jungle, semiarid zone and tropical rainforest ecosystems. Three Rhynocoris species R.fuscipes, R.kumarii, R.longifrons and C.soosai, and R.atkinsoni are recorded in all the three major ecosystems as well as in agrocosystems. A similar observation was noted for the holoptiline H.melanospilus.

 

Among Peiratinae, seven are exclusively present in tropical rainforests, four in semiarid zones and two in scrub jungles. C.brevipennis, E.gangeticus and E.tuberculatum are seen in scrub jungles, semiarid zones and adjacent agroecosystem. E.nigrochripes, E.tibialis and P.affinis are found in all the three major ecosystems as well as in agroecosystems. The latter two are also found light attracted. In Peiratinae, the habitats of many light attracted species are not known.

 

Among Reduviinae as observed for Harpactorinae, tropical rainforests harbour exclusively sixteen out of total sixty one  species observed. Such exclusive presence is also found  in scrub jungles and semiarid zones (eight and five  species respectively). A.apicata, A.flavipes, A.zebracia, Acanthaspis sp., P.nigerrima, R.delicatula are recorded in the scrub jungles and semiarid zones. A.subrufa and Acanthaspis sp. share tropical rainforests and semiarid zones. Similarly, C.dermata, E.maculatus and Paralenaeus sp. share scrub jungles and tropical rainforests.  Ten reduviines are found in agroecosystems out of which seven belong to the genus Acanthaspis. A.pedestris, A.quinquespinosa, A.rama, A.sexguttata, A.siva, A.tergemina, A.trimaculata, E.slateri and V.sinensis are found in all the three major ecosystems as well as in agroecosystems.

Two saicines are exclusively present in semiarid zones, one in semiarid zones and agroecosystems, one in tropical rainforests and agroecosystems and one in agroecosystems alone. Interestingly, none of them is found in scrub jungles. Out of the five species recorded, three are light-attracted.

 

Among Salyavatinae, one species, each in semiarid zones and scrubjungles and two species in  tropical rainforests are exclusively present. Three species, L.annulosa, N.frontispina and P.brachialis are found in all the  three major ecosystems. N.frontispina is also found in agroecosystems and P.brachialis is found light attracted.

 

Among 38 stenopodaines, six are exclusively present in tropical rainforests. Here comparatively more members (14 species) are found in agroecosystems. A single stenopodaine O.notatus occupy all the three major habitats as well as in agroecosystems. Many species share scrub jungles as well as semiarid zones as their dwellings.

 

Among triatomines, T.rubrofasciata and L.confumus and L.costalis are recorded from human inhabitations and semiarid zones whereas a Linshcosteus sp. from scrub jungles.

 

The habitat known for all the three tribelocephalines is tropical rainforest, but one species also  lives in semiarid zones.

 

All the characteristic species of tropical rainforest are usually found in either arboreal or litter dwelling and are conspicuously diurnal. The semiarid zone and scrub jungle species are found usually in concealed habitats like underneath the boulders or the underside of loose bark of trees and they are crepescular.

 

MORPHOLOGICAL DIVERSITY

Structural and behavioural adaptations of assassin bugs are intimately related with their ecological diversity. Hence, diversity of structure is analysed to understand their interrelationship with ecological diversity under three major distinguishable structures viz., rostrum, tibial pad and wing.

 

 

Rostrum

 

The rostrum of assassin bugs are categorized into four major types. They are straight, slightly curved, curved and acutely curved. Majority of the assassin bugs  have slightly curved rostrum (49%) followed by acutely curved (31%), curved (15%), and straight rostrum (5%). Centrocnemines, ectrichodiines and physoderines have uniformly either acutely curved or curved rostrum except N.therasii which has slightly curved rostrum. None of them has straight rostrum. Apiomerines, ectionoderines, emesines, holoptilines and triatomines uniformly have straight rostrum. Among harpactorines, 11 species have straight rostrum, 23 species have curved rostrum and others have slightly curved rostrum. None of them has acutely curved rostrum. Peiratines and reduviines have uniformly acutely curved ‘bow’ shaped rostrum. Saicines, salyavatines, stenopodaines and tibelocephalines have uniformly slightly curved rostrum (table 3, fig. 3).

 

Tibial pad

 

Assassin bugs are broadly grouped into two categories i.e., those with tibial pads or fossula spongiosae and those without tibial pads. Tibial pads are adaptive structural modifications of tibial ends involve in predation.

One hundred sixty one species possess tibial pads both in the fore- and midtibiae whereas S.flavipes (Peiratinae) has tibial pads only in foretibiae. Tibial pads are well developed both in the fore- and midtibiae of ectinoderines, ectrichodiines, physoderines and reduviines except in N.therasii of Ectrichodiinae  and P.nigerrima of Reduviinae. The former has rudimentary tibial pads whereas the lattter has apical tibial pads. Members of Apiomerinae,  Emesinae, Harpactorinae, Holoptilinae, Saicinae, Stenopodainae and Tribelocephalinae are generally devoid of tibial pads. But C.picticollis of Stenopodainae has well developed tibial pads. Differential level of rudimentary tibial pads and tibial combs are observed in many species of these six subfamilies. Except S.flavipes which has only the foretibial pad all other peiratines have well developed tibial pads. Two Petalocheirus species have rudimentary tibial pads and L.annulosa has apically projected tibial pads. Among Triatominae, two species have tibial pads both in the fore- and midtibiae (table 3, fig. 4).

Wing

 

Assassin bugs exhibit diversity in wings. There are alate, brachypterous, micropterous and apterous reduviids. Moreover, in certain species alary polymorphism and sexual dimorphism are seen.

 

Alate reduviids are dominant (84%) followed by apterous (9%), micropterous (2%) and brachypterous (2%) reduviids. Polymorphism and sexual dimorphism in wing development and colour with intersexual variations are seen in 12 species.

 

Apiomerines, centrocnemines and ectinoderines are fully alate.

 

Among ectrichodiines Ectrychotes (except dimorphic E.bharathi,) Guionius, Labidocoris, Stegius and Synectrychotes are alate. Neohaematorrhophus is polymorphic. Aptery is almost totally pronounced in Haematorrhophus and Hemihaematorrhophus and partially (50%) in Scadra.

 

Among emesines, members of Bagauda, Emesopsis, Empicoris, Gardena, Myiophanes and Stenolemus are fully alate. Ghilianella, Ischnobaena  and Ischnobaenella are fully apterous. Ploiara has both alate and apterous forms.

 

Except the apterous rhaphidosomatines all other harpactorines are alate.

 

Holoptilines are only alate.

 

In Peiratinae, Catamiarus is brachypterous; Ectomocoris comprises of  alate (12), micropterous (5), polymorphic (2) and sexually dimorphic (2) reduviids; Lestomerus is alate and Peirates and Sirthenea are totally alate with one sexually dimorphic species (L.affinis, male is alate).

 

The lone member of Physoderinae is alate.

 

In Reduviinae, Acanthaspis is dominated by alate (26) followed by apterous (7) and micropterous (7) species. A.siva is alate with polymorphism in prothorax and leg colouration. Alloeocramum and Mesacanthaspis are micropterous. Apechtia, Neoacanthaspis, Paralenaeus, Pasira, Pasiropsis, Reduvius, Sminthocoris and Velitra are alate. Both males and females are alate in three Edocla specis.

 

In Saicinae, except P.femoralis all other recorded members are alate.

 

In Salyavatinae, Lisarda and Petalocheirus are alate; Nudiscutella is apterous and Paralisarda is either apterous or micropterous.

 

Apterous condition is found in Ectrichodiinae, Emesinae, Harpactorinae, Reduviinae, Saicinae, Salyavatinae and Stenopodainae. Micropterous condition is seen only in three subfamilies viz., Reduviinae, Salyavatinae and Saicinae. Brachypterous condition is recorded only in Peiratinae and Stenopodainae. Sexual alarydimorphism is seen only in Peiratinae and Reduviinae whereas Polyalarymorphism is present also in Ectrichodiinae in addition to Peiratinae and Reduviinae.

 

In the sexually dimorphic forms, the males are generally alate whereas the females are apterous or micropterous or brachypterous (table 3, fig. 5).

 

BEHAVIOURAL AND BIOLOGICAL DIVERSITY

 

Predation

 

Except the millipede feeding Haematorrhophus species (Ectrichodiinae) and the haematophagous triatomines all other assassin bugs  are entomosuccivorous. Many of them are feeding on insect pests.

Generally, the endemic tropical rainforest species are devoid of tibial pads and their rostrum is either straight or slightly curved. The endemic species of scrub jungles and semiarid zones have well developed tibial pads and their rostrum is acutely curved or curved. The forelegs of endemic apiomerines and ectrichodiines of tropical rainforests are smeared with resins and kept in a raised position in front of them. They wait in the position for small flying insects to get entangled and trapped, which are ultimately fed. In many of these species with such sticky-trap feeding, the foerlegs are never used for locomotion. Moreover, they do not use their rostrum to capture their prey.

 

Similarly endemic tropical rainforest emesines as well as emesines in scrub jungle and semiarid zones use their raptorial long forelegs, armed with spines and tubercles to capture their prey. These predators wait on vegetation and with a quick flicking movement of the raptorial forelegs they prey is caught.

 

Certain endemic tropical rainforest reduviines, salyavatines and stenopodaines with their well developed forelegs possessing tibial pads wait at  places where their prey types frequent like termitaria. These wait and grab type predators, on seeing the prey, quickly approach the prey and grab them.

 

Many of the endemic tropical rainforest harpactorines and those live in the scrub jungle and semiarid zone, on sighting their prey, approach it in slow gait and extend their long straight or slightly curved rostrum and jab the prey and inject toxic saliva. They usually keep their rostrum inserted into wriggling prey. They use their forelegs only when they fail to manage their prey with their inserted rostrum. These predators rely upon their rostral strength rather than tibial strength. Moreover, they seldom actively chase the prey. Congregational feeding is common in endemic tropical rainforest forms.

 

Majority of the endemic scrub jungle and semiarid zone assassin bugs with their short powerful legs actively chase their prey, pounce over them and grab and hold them with tibial pads of fore- and midlegs.

 

Endemic triatomines of human dwellings and of scrub jungles and semiarid zones are vertebrate blood feeders. Temperature gradient emanating from their hosts initiates feeding response of a hungry insect.

 

Mating

 

In the mating behaviour, precopulatory riding is observed only in harpactorines and it is well pronounced in tropical rainforest endemic species. Such behaviour is either absent or less pronounced in semiarid zone and scrub jungle forms. Lateral copulation is the characteristic feature in Reduviinae, Stenopodainae, Triatominae and Harpactorinae. End-to-end copulation is a common feature in Peiratinae.

 

Defensive behaviour

 

Adaptive nymphal camouflaging as defensive behaviour is found only among the members of Reduviinae, Salyavatinae and Triatominae which are characteristic species of semiarid zones and scrub jungles. The nymphal instars of endemic tropical rainforest species are found armoured with straight as well as club-shaped hairs as a protective measure. Another defensive behaviour, feigning death is  also common among tropical rainforest species. However, the nymphal cannibalism is uniformly prevalent among the characteristic species of semiarid zones, scrub jungles and tropical rainforests, indicating their predatory character irrespective of their habitats and the levels of availability of their prey fauna.

 

Egg and Oviposition

 

Assassin bugs exhibit diversity not only in the shape of the eggs but also in their egg laying pattern.

 

Egg laying habits of only 115 species are known. Fifty eight  species glue thier eggs with one another and to the substratum with cementing material whereas 57 species lay their eggs loosely (table 3; fig. 6).

Ectrichodiines lay elongately oval eggs loosely, except N.therasii and Scadra sp. which glue their eggs to the substratum. An emesine also lay elongately oval eggs loosely. Harpactorines lay elongate eggs. Except Rhaphidosoma,  harpactorine eggs are laid in cluster, glued to each other as well as to the substratum. The egg masses are generally exposed. Holoptilines also glue their elongately oval eggs. Peiratines lay elongately oval eggs loosely deep inside the soil. Reduviines lay globose eggs loosely in soil or crevices except the Edocla species which lay their eggs in clusters. Reduiviines have the tendency to glue their eggs with their fresh excreta. Gluing of eggs to the fresh excreta is also observed in Peiratinae and Stenopodainae. Members of Salyavatinae, Stenopodainae and Triatominae lay globose eggs unexposed without any cementing material.

 

Based on the egg laying pattern, assassin bugs are categorized into five  groups : 1) eggs laid in single cluster and cemented to each other partially and to the substratum (predominantly in Ectrichodiinae) 2) eggs laid in single cluster and the eggs are glued to each other longitidinally, basally and to the substratum (predominantly in Harpactorinae) 3) each egg individually cemented to the substratum in isolation (predominantly in Holoptilinae) 4) glued to fresh faecal matter (predominantly in Ectrichodiinae, Reduviinae, Peiratinae, and Stenopodainae and 5) eggs loosely strewn around erratically without any pattern (predominantly in Reduviinae, Peiratinae, Stenopodainae, and Salyavatinae). The endemic tropical rainforest species predominantly come under the first two categories of egg laying whereas the scrub jungle and semiarid zone endemics exhibit categories 3 to 5 (table 3; fig. 6).

 

 

Biology

 

Apart from distinguishable adaptive strcutural and behavioural adaptations of endemic tropical rainforest forms in one hand and endemic scrub jungle and semiarid zone forms in the other hand, they also exhibit biological diversity.

 

Hatching percentage is comparatively greater among the harpactorines than among reduviines, peiratines, triatomines, stenopodaines and salyavatines, separately. Generally, endemic tropical rainforest assassin bugs exhibit higher fecundity and hatchability than their counterparts in scrub jungles and semiarid zones. Eclosion and emergence periodicities in harpactorines are observed generally in forenoon and afternoon (diurnal) whereas these periodicities among the members of Reduviinae, Peiratinae, Triatominae, Stenopodainae and Salyavatinae are mostly found at dusk or at night (crepuscular). The incubation and stadial periods of tropical rainforest forms are shorter than those of scrub jungle and semiarid zone species. The endemics of tropical rainforest are generally multivoltine with shorter stadia whereas those of scrub jungles and semiarid zones are univoltine or bivoltine with longer stadia.

 

Biocontrol agents

 

Fifty species are recorded as biocontrol agents. They are predominant among harpactorines (thirty four) followed by in reduviines (eight), peiratines (five), ectrichodiines (two) and stenopodaines (one). Biocontrol agents are not recorded from Apiomerinae, Centrocneminae, Ectinoderinae, Emesinae, Holoptilinae, Physoderinae,  Saicinae, Salyavatinae and Tribelocephalinae.

 

Domestic pests

 

Three triatomine domestic pests (haematophagous) are seen.

 

DISCUSSION

The richest taxonomic diversity in terms of species diversity is apparently exhibited by harpactorines followed by reduviines. Though, 37 peiratines are recorded, the species diversity is lesser (six genera) than that of Ectrichodiinae (31 species and 10 genera) and Stenopodainae (31 species and 11 genera). Emesinae though comprises lesser number of species (16) they are equivalent to that of  Stenopodainae with eleven genera. Interestingly nine salyavatines are grouped under four genera whereas six triatomines are present under only two genera. Members of Apiomerinae, Centrocneminae, Holoptilinae, Physoderinae,  Saicinae and Tribelocephalinae are represented by a genus, each. However, a species diversity index was calculated (Ambrose, 1999) by correlating the number of species and genera in a subfamily and considering the species number as unity and the genus number as proportionate value (of species unity). According to this calculation lower the index number greater the species diversity and accordingly subfamilies of Reduviidae are ranked as follows: Apiomerinae (1) < Ectinoderinae (1) < Physoderinae (1.0) < Emesinae (0.63) < Centrocneminae (0.5) < Holoptilinae (0.5) < Salyavatinae (0.44) < Stenopodainae (0.35) < Triatominae = Tribelocephalinae (0.33) < Ectrichodiinae (0.31) < Harpactorinae (0.24)  < Reduviinae (0.22) < Saicinae (0.2) < Peiratinae (0.16).

 

Majority of the assassin bugs especially those living in semiarid zones and scrub jungles prefer to live in concealed microhabitats. Interestingly assassin bugs which prefer exposed microhabitats are more common in tropical rainforests and are diurnal whereas those live in concealed microhabitats are crepuscular. Exposed microhabitats and diurnal behaviour are closely related to their wait and pin/jab/grab mode of feeding whereas concealed microhabitats and crepuscular behaviour are facilitating their chase and grab or pounce and grab mode of feeding. The former adaptation is suitable for tropical rainforest ecosystem where the prey fauna is not scarce whereas the latter is suited for prey-scarce semiaridzone and scrub jungle ecosystems.

 

Majority of the assassin bugs live in tropical rainforests. Out of the habitat known 303 assassin bugs reported in this chapter, 108 reduviids exclusively live in tropical rainforests. These species are considered endemic to tropical rainforest- ecosystems. Such an endemism is comparatively very lesser for semiarid zones (26 species) and scrub jungles (24 species). It has been suggested that tropical rainforest is the ecosystem where reduviids have lived and they might have gradually inhabitated scrub jungles and semiarid zones as the transition of tropical rainforest to scrub jungle and to semiarid zone has taken place.

 

As the tropical rainforest transition to scrub jungle and semiarid zone has taken place, the once endemic tropical rainforest species have occupied scrubjungle and semiarid zone with structural,  behavioural and biological adaptations.

 

For instance, most of the tropical rainforest, diurnal, exposed microhabitat living species are lightly coloured with a reddish tinge and without  any warning colouration. Such a colouration helps the tropical rainforest endemic species to comouflage with the rich vegetation of their habitats. But most of the semiarid zones and scrub jungle assassin bugs are  crepuscular, concealed microhabitat living species  exhibit warning colouration (black and yellow). The warning colouration of scrub jungle and semiarid zone assassin bugs are the characteristic feature of their drought pone, prey scarce ecosystems.

 

In addition to colouration, the cuticle of tropical rainforest endemic  species is comparatively softer than that of scrub jungle and semiarid zones species which have harder cuticle with rich setose hairs, spines and tubercles. The harder cuticle with setose hairs, spines and tubercles is also an adaptation to withstand the drought prone climatic adversities and concealed microhabitats of semiarid zones and scrub jungles.

 

Nontibial pad reduviid predators endemic to tropical rainforests are considered as timid predators since they do not employ their forelegs in prey capturing. During the course of evolution of their ancestral saprophagy to carnivory and from timid predators to aggressive assassins, their maxillary stylets have also undergone structural as well as functional changes. Timid predators which predate on smaller prey of tropical rainforest at random have relatively better formed maxillary barbs than agressive predators of scrub jungles and semiarid zones. During the course of evolution loss of maxillary barbs, widening of salivary canal, increase of guidance of the route of the central stylet bundle, development of a maxillary lever that limits the protrusion of the central stylets, reduction of apical plate as intercalary plate of the rostrum and reduction in the mobility of last rostral segment might have taken place.

Endemic scrub jungle and semiarid zone species  are also found withstanding prolonged starvation when compared to the tropical rainforest forms. It has been considered as an adaptation in the prey-scarce ecosystem. Moreover, the structural adaptations of the endemic species of scrub jungles and semiarid zones such as acutely curved rostrum as well as well developed tibial pads are correlated to their better predatory efficiency.

 

Generally the endemic tropical rainforest forms lay more number of elongate or elongately oval eggs in less number of batches or clusters and glue their egg massess either to the substratum or in the vegetation and egg masses are exposed.

 

The semiarid zone and scrub jungle forms lay lesser number of spherical or oval eggs in more number of batches, without any cementing material either in crevices or deep inside the soil. Their eggs are never found exposed in the field.

 

Tropical rainforest endemics have prolonged mating behaviour  with a characteristic precopulatory riding, diurnal behaviour, exposed oviposition with higher fecundity in less number of batches of eggs, higher hatchability, shorter incubation and stadial periods, predominantly multivoltine etc. The tropical rainforest characteristics are more suited to the prey-rich, droughtless habitat with less threat from biotic (e.g. predators) and climatic adversities. In contrast, scrub jungle and semiarid zone endemics have short mating behaviour resembling agressive predation, concealed oviposition with lesser fecundity in more number of batches of eggs, poor hatchability, larger incubation and stadial periods, predominantly univoltine or bivoltine etc. The scrubjungle and semiarid zone characteristics are more suited to prey-scarce, drought-prone habitats with more threat from biotic and abiotic adversities.

 

The structural, behavioural and biological adaptations of endemic assassin bugs of tropical rainforests, scrub jungles and semiarid zones can be better understood with knowledge on the transformation of tropical rainforest ecosystems into scrub jungle and to semiarid zone ecosystems.

 

The assassin bugs once predominantly present in the tropical rainforest ecosystem might have the following characteristics: 1) complex stylets and genitalia 2) timid predators, tibia without tibial pads or with tibial combs, spines, spurs etc. 3) fully alate 4) soft cuticle without warning colouration 5) generally polyphagous 6) predominantly arboreal and diurnal 7) gluing eggs basally and vertically in the form of a ootheca 8) exhibit congregational feeding 9) exhibit precopulatory riding during mating 10) high fecundity in less number of batches 11) good hatchability 12) shorter incubation and stadial periods and 13) predominantly multivoltine. During the course of their migration from tropical rainforest  to drought prone scrub jungle and semiarid zone. They might have attained the following characteristics : 1) loss of complex stylets and genitalia 2) aggressive predators with increased development of tibial pads 3) alary polymorphism, such as sexual dimorphism, aptery, brachyptery and alate condition 4) hard cuticle with warning colouration 5) increasingly monophagous 6) predominantly crepuscular 7) gluing eggs only basally or burying individual eggs deep inside the soil or exhibiting tendency to glue the eggs to fresh excreta or ovipositing eggs solitary at random 8) adaptive nymphal camouflaging (Reduviinae and Salyavatinae) 9) lower fecundity in more number of batches 10) poor hatchability and 11) predominantly univoltine or bivoltine. (Ambrose, 1980; 1987a, 1987b, 1996, 1999, 2000; Livingstone and Ambrose, 1984; Vennison, 1988; Murugan, 1988; Ravichandran, 1988; Ambrose and Livingstone, 1989; Ambrose and Vennison, 1990a, 1990b; Vennison and Ambrose, 1990; Sahayaraj, 1991; Kumaraswami, 1991; Rukmani, 1992; Kumar, 1993; and Das 1996; Ambrose and Ambrose, 1996a,b).

 

ACKNOWLEDGEMENTS

 

The author is grateful to Prof. D.Livingstone, Madras Christian College, Chennai, India; Prof. Carl. W. Schaefer, University of Connecticut, Connecticut, U.S.A.; Mr. Mick D. Webb, The Natural History Museum, London, U.K.; Dr. Richard C. Froschner,  Dr. Thomas J. Henry, Dr. Dan A. Polhemus, Smithsonian National Museum of Natural History; Washington, DC, U.S.A.; Dr. John R. Ruberson, University of Georgia, Tifton, U.S.A. for their assistance at various levels of this study and the authorities of St. Xavier’s College, Palayankottai for facilities, especially Rev. Fr. Lourdusamy, S.J. (Principal), Rev. Fr. D. Selvanayakam, S.J. (Secretary).

 

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Ambrose, D.P. (1987a): Assassin bugs of Tamil Nadu and their role in biological control  (Insecta : Heteroptera: Reduviidae). In: Advances in biological control research in India. K.J. Joseph and U.C. Abdurahiman, (ed.), (Calicut; M/S Printex Ltd), pp. 16-28.

 

Ambrose, D.P. (1987b): Biological, behavioural and morphological tools in the biosystematics of Reduviidae (Insecta : Heteroptera : Reduviidae), Proc. Indian Acad. Sci. (Anim. Sci), 96: 499-508.

 

Ambrose, D.P. (1996): Biosystematics, distribution, diversity, population dynamics and biology of reduviids of Indian subcontinent- an overview. In: Biological and cultural control of insect pests, an Indian scenario, D.P. Ambrose (ed.), (Tirunelveli, India: Adeline Publishers) pp. 93-102.

 

Ambrose, D. P. (1999): Assassin bugs. Science publishers, New Hampshire, USA and Oxford and IBH Publ.Co. Pvt. Ltd., New Delhi, India, pp. 337.

 

Ambrose, D.P. (2000). Assassin Bugs (Reduviidae excluding Triatominae) In: Heteroptera of   economic importance. C. W. Schaefer, A. R. Panizzi (eds.), CRC Press, Florida, U.S.A. p.695-712.

Ambrose, A.D. and Ambrose, D.P. (1996a): Multidisciplinary facets of insect biosystematics - an overview. In: Biological and cultural control of insect pests, an Indian scenario, D.P.  Ambrose (ed.,), (Tirunelveli, India: Adeline Publishers) pp. 5-39.

 

Ambrose, A.D. and Ambrose, D.P. (1996b): Biological tools in the biosystematics of three subfamilies of Reduviidae  (Insecta : Heteroptera). In: ibid., p. 40-48.

Ambrose, D.P. and Livingstone, D. (1989): Diversity of eggs and oviposition behaviour in assassin bugs; Environment and Ecology, 7: 582-590.

 

Ambrose, D.P. and Vennison, S.J. (1990a): Camouflaging behaviour in an acanthaspidine assassin bug Edocla slateri Distant  (Insecta : Heteroptera : Reduviidae), Hexapoda, 2: 100-103.

 

Ambrose, D.P. and Vennison, S.J. (1990b): Diversity of spermatophore capsules in reduviids  (Insecta : Heteroptera : Reduviidae), Mitt. Zool. Mus. Berl., 66: 309-317.

 

*Das, S.S.M. (1996): Biology and behaviour of chosen predatory hemipterans; Ph.D. thesis, Madurai Kamaraj University, Madurai, India.

 

Distant, W.L. 1902. The fauna of British India including Ceylon and Burma, Rhynchota Vol. II (Heteroptera); (London: Taylor and Francis Ltd.,) pp. 1 - 503.

 

Distant, W.L. 1910. The fauna of British India including Ceylon and Burma, Rhynchota Vol. V. (Heteroptera: Appendix); (London: Taylor and Francis Ltd.,) pp. 1 - 362.

 

*Kumar, S.P. (1993): Biology and behaviour of chosen assassin bugs,  (Insecta : Heteroptera : Reduviidae), Ph.D. thesis, Madurai Kamaraj University, Madurai, India.

 

*Kumaraswami, N.S. (1991): Bioecology and ethology of chosen predatory bugs and their potential in biological control, Ph.D. thesis, Madurai Kamaraj University, Madurai, India

 

 Livingstone, D., Ambrose, D.P. (1984): Adaptive modifications of the Reduviidae of the scrub jungles and semiarid zones of the Palghat gap India an evolutionary approach. J. Bombay. Natu. Hist. Soc., 81: 583 - 595.

 

Maldonado Capriles, J.M. (1990):  Systematic catalogue of the Reduviidae of the world  (Insecta : Heteroptera). University of Puerto Rico. (Mayaguez). pp. 694.

 

Murugan, C. (1988): Biosystematics and ecophysiology of the tibiarolite assassin bugs  (Heteroptera : Reduviidae) of southern India. Ph.D. thesis, Bharathiar University, Coimbatore, India.

 

Ravichandran, G. (1988): Biosystematics and ecophysiologyof the non-tibiarolite assassin bugs  (Heteroptera: Reduviidae) of southern India. Ph.D. thesis, Bharathiar University, Coimbatore, India.

 

Rukmani, J. (1992): Multidisciplinary tools in the biosystematics of Reduviidae  (Insecta : Heteroptera : Reduviidae), Ph.D. thesis, Madurai Kamaraj University, Madurai, India.

 

*Sahayaraj, K. (1991): Bioecology, Ecophysiology and Ethology of chosen predatory hemipterans and their potential in biological control  (Insecta : Heteroptera : Reduviidae), Ph.D. thesis, Madurai Kamaraj University, Madurai, India.

 

*Vennison, S.J.  (1988): Bioecology and ethology of   assassin bugs,  (Insecta : Heteroptera : Reduviidae), Ph.D.   thesis, Madurai Kamaraj University, Madurai, India.

 

Vennison, S.J. and Ambrose, D.P. (1990): Diversity of eggs and ovipositional behaviour in reduviids  (Insecta: Heteroptera : Reduviidae) from South India; Mitt. Zool. Mus. Berl., 66: 319-331.

 

* with the guidance of the author.