Applied evolutionary ecology of insects of the subfamily Bruchinae (Coleoptera: Chrysomelidae)

Abstract

Bean beetles of the subfamily Bruchinae (formerly, the family Bruchidae) include notorious pests of stored legumes, Callosobruchus, Caryedon, Acanthoscelides and Zabrotes that are able to feed and reproduce on dried beans and peas. Here, I review recent findings on the ecology, phylogeny, invasion and evolution in the bean beetles, based on field investigation of host plants and molecular studies. Possible future application of the new knowledge to weed and pest control is proposed, such as potential utility of the seed predators for modest control of beneficial yet invasive ('conflict') plants and new control methodology of pest bean beetles.

Global legume diversity assessment: Concepts, key indicators, and strategies

“…Native bruchines are absent in arctic areas and Pacific islands and scarce in Australia (Borowiec, 1987). Most species of bruchines are oligophagous, i.e., feeding only on a few related legumes (Johnson, 1981a;Delobel & Delobel, 2006), with the exception of stored legume pests (Tuda, 2007) and post-dispersal seed predators (Morse & Farrell, 2005). Predation by bruchines is considered to affect the pattern of seed dispersal, evolution of various resistance traits in legumes and counter-evolution in bruchines (Janzen, 1969;Rosenthal & al., 1977;Johnson, 1981b).…”

Warp-speed adaptation to novel hosts after 300 generations of enforced dietary specialisation in the seed beetle Callosobruchus maculatus (Coleoptera: Chrysomelidae: Bruchinae)

“…These are a common pest species of stored legumes and are extremely detrimental to economic interests and food security throughout the tropical and subtropical world (Boeke et al, 2004). The species originates from West Africa where the cowpea (Vigna unguiculata) is their host legume, but populations of C. maculatus have also spread to temperate regions, following human trade, and have adopted several novel agriculturally-cultivated host species associated with these range shifts (Tuda, 2007;Tuda et al, 2014). The beetles exist in small numbers in the fi eld but undergo exponential population growth when the legumes are moved to storage (Messina, 1998).…”

“…Due to a short generation time and high fecundity, they are responsible for 90% of all insect damage to stored cowpeas (Caswell, 1981), and they also represent a signifi cant threat to other stored legumes as alternative host races have spread throughout the world (Tuda et al, 2014). Although this makes C. maculatus a persistent problem pest species, it also makes them ideally suited for studies investigating the adaptation of species to new native hosts (Tuda, 2007).…”

Does height of exposure in the canopy influence egg mortality inAcanthoscelides macrophthalmus(Coleoptera: Chrysomelidae), a biological control agent ofLeucaena leucocephalain South Africa?

“…Although the beetle has become established in several countries following accidental introductions in contaminated seeds (e.g. Delobel & Johnson, 1998;Kingsolver, 2004;Raghu, Wiltshire, & Dhileepan, 2005;Tuda, 2007), South Africa is the only country to have deliberately introduced it for biological control (Olckers, 2011). The thin-walled (papery) seed pods of L. leucocephala are passively dehiscent (Henderson, 2001), and canopy-held pods release their seeds intermittently onto the soil surface.…”

“…The thin-walled (papery) seed pods of L. leucocephala are passively dehiscent (Henderson, 2001), and canopy-held pods release their seeds intermittently onto the soil surface. As is typical of bruchine beetles, A. macrophthalmus females oviposit on the outer surfaces of the seed pods or loose seeds of L. leucocephala and the developing endophagous larvae destroy the seeds (Shoba & Olckers, 2010;Tuda, 2007). The beetle was considered to have potential for limiting the build-up of soil seed banks, restricting seed dispersal and hence curbing the invasiveness of L. leucocephala in South Africa (Olckers, 2011).…”