Reduvid bugs (Reduvioidea) – of which there are more than 7,000 named species – have evolved a diverse range of structural and behavioral adaptations to enable them to capture prey (4), including the application of sticky substances (“sticky traps”) to their forelegs by so-called resin bugs. Such ‘sticky trap predation’ is known from species in both the New and Old Worlds:
“Unique among known sticky trap predators, assassin bugs (Reduviidae) have evolved both exogenous and endogenous sticky trap predatory mechanisms: some trap their prey with sticky plant resins, some scavenge insects entrapped by sticky plant trichomes and others self-produce sticky secretions.” (Zhang et al., 2016) (3)
I came across some resin bugs on a ‘resin trap’ – a natural or human-induced outflow of resin at the base of a large dipterocarp resin tree – which I wrote about in a previous blog (5). Recently, I came across more of these amazing insects (see below) and thought it was worth including some additional photographs of them, to show their adaptations for capturing prey. The bugs cover themselves with plant resin, particularly the front legs, which helps them to capture prey, such as bees.
Some of the bugs have thick applications of resin on their fore-legs. Precisely what strategy they use to capture prey, sit and wait; wave their legs around; creep up on them (?), I am not sure of.
I came across one sitting in a hole in the resin trap (below) but they were generally fairly active, albeit moving somewhat slowly (as you might if covered with a sticky resin!).
The bees also collect resin for their nests and hover above the resin trap before landing on the sticky resin (below).
There were also lots of ants foraging for prey items on the tree and in the resin trap; probably Oecophylla smaragdina. Presumably they are clever enough to steer clear of the resin bugs, although I came across these two individuals quite close to each other.
I still do not have a firm identification of the resin bugs shown here, but they are probably a sub-species of Amulius malayus, or a closely-related species. The resin bugs must moult at some stage, and there was evidence of either cast skins (exuviae) or dead bugs within the resin (below).
There must be a lot to find out about these insects and they would make a fascinating study, although one would have to be careful of the ants’ nests which are found nearby. I quickly became covered with ants on one occasion when photographing the bugs!
- Silva, Alexandre Coletto da and Gil-Sntana, Hélcio R.. Predation of Apiomerus pilipes (Fabricius) (Hemiptera, Reduviidae, Harpactorinae, Apiomerini) over Meliponinae bees (Hymenoptera, Apidae), in the State of Amazonas, Brazil. Rev. Bras. Zool. [online]. 2004, vol.21, n.4 [cited 2017-11-29], pp.769-774
- Weirauch, C., Bérenger, J. M., Berniker, L., Forero, D., Forthman, M., Frankenberg, S., … & Marshall, S. A. (2014). An illustrated identification key to assassin bug subfamilies and tribes (Hemiptera: Reduviidae). Canadian Journal of Arthropod Identification, 26(2), 1-115.
- Zhang, J., Weirauch, C., Zhang, G., & Forero, D. (2016). Molecular phylogeny of Harpactorinae and Bactrodinae uncovers complex evolution of sticky trap predation in assassin bugs (Heteroptera: Reduviidae). Cladistics, 32(5), 538-554.
- Zhang, J., Gordon, E. R., Forthman, M., Hwang, W. S., Walden, K., Swanson, D. R., … & Weirauch, C. (2016). Evolution of the assassin’s arms: insights from a phylogeny of combined transcriptomic and ribosomal DNA data (Heteroptera: Reduvioidea). Scientific reports, 6, srep22177.