Apanteles Foerster, 1863

Kallyadan, Sreejina Sreedharan & M., Nasser, 2024, Making shelter for enemies: parasitoid-induced shelter-building behaviour in Paraponyx stagnalis, Journal of Natural History 58 (21 - 24), pp. 658-673 : 661

Genus Apanteles Foerster, 1863

( Braconidae : Microgastrinae )

The largest genus of Microgastrinae , Apanteles , contains more than 600 known species that can be found worldwide. Traditionally, all braconid species with an open forewing areolet were named Apanteles . The assemblage of species in the genus Apanteles is still enormous and diverse. Identifying Apanteles sp. poses a challenge due to the numerous similarities in their morphological characteristics ( Fernandez-Triana et al. 2020). In terms of both economic value and diversity of species, Microgastrinae is by far the most significant group of parasitoids in Lepidoptera worldwide ( Whitfield 1995, 1997). With the help of venom and the effects of polydnavirus (PDV) on the host’s immune and endocrine systems, adult female wasps typically oviposit into early-instar host larvae (although a few species have been known to oviposit into host eggs), where the wasp eggs hatch and larval development occurs (as summarised by Whitfield et al. 2018).

The female Apanteles lays the eggs within the host larvae ( Gupta et al. 2016). After 6–10 days of parasitisation, the Apanteles larvae will develop inside the body of the larval Lepidoptera until emergence ( Boling and Pitre 1970). There are three larval instars in Apanteles . The hymenopteriform is the third instar ( Figure 5 (a)). The pupa belongs to the exarate type, meaning that its appendages are free and not attached to the body. Shortly after emerging from the host, it develops inside the cocoon ( Figure 6 (b)) constructed by the mature final-instar larva. They are solitary or gregararious endoparasitoids (koinobionts) of Lepidoptera larvae ( Shaw and Huddleston 1991; Whitfield 1997; Whitfield et al. 2018).

Figures

Figure 5. Biology of Apanteles species. (a) Parasitoid larva near the host (Paraponyx stagnalis) larval remnant. (b) Parasitoid pupa with an emergence hole. (c) Parasitoid cocoon shelter in the rice leaf. (d) Parasitised P. stagnalis larval shelter in grass species Digitaria. (e) Parasitised rice case worm leaf shelter.

Figure 6. Leaf shelter of Paraponyx stagnalis. (a) Tubular case of late-instar larva. (b,c) Tubular cases of early-instar larvae. (d) Caterpillar making leaf shelter. (e,f) Caterpillars’ bright brownish-orange head protruding from the tubular case. (g) Silk covers the case’s interior, storing a small layer of water.