Two-Spotted Assassin Bug

Domain: Eukarya

Kingdom: Arthropoda

Class: Insecta

Order: Hemiptera

Family: Reduviidae

Genus: Platymeris

Specieas: Platymeris biguttatus

General Characteristics: The Two-Spotted Assassin Bug (Platymeris biggattatus) is a bug found primarily in west and southwest Africa and is a member of the "Assassin Bugs," a group of ~300 species of bugs in the family Reduviidae that are predatory and attack their prey (which are often much larger than themselves) by injecting them with toxins that paralyze the victim before then liquefying the inner tissues and then consuming them; this has been shown to be an effective feeding method of consuming up to 99% of the prey's body weight. The two-spotted assassin bug is one of the better-studied members of the group, and like its peers uses its sharp proboscis capable of piercing the thick exoskeleton of potential prey (usually cockroaches, caterpillars, beetles, and other such insects that may be nearby), injecting the saliva which contains the enzymes to liquefy the tissue, and then using the proboscis as a kind of "straw" to then consume the fluids. To humans, however, the bite is only a bit more painful than a bee sting (image 1), though is also capable of spitting a kind of venom that can cause temporary blindness.

Image 1: an assassin bug bite on a human. Though not capable of the large-scale liquefaction seen in prey species, it still causes a large amount of pain.

Habitat: Along with most of the other members of the assassin bug family, the Two-Spotted Assassin Bug makes its home in various temperate areas on the African continent, with a broad range of habitats across the majority of the continent and clusters of "very suitable" habitat cropping up variously along the eastern and western edges (image 2). This correlates with it's preferred climate of moderate to high temperatures (around 76 to 83 degrees Fahrenheit) and intermediate amounts of moisture or rainfall. It has been noted, however, that these areas and climates are a niche that overlaps significantly with P. rhadamanthus, another type of assassin bug, which could lead to "conflicts" for habitat and space (Chlond et al. 2015). Within these habitats, they can most often be found in their nests, which are typically hollow and / or rotting tree stumps or logs.

Image 2: geographical dispersion of habitat for the Two-Spotted Assassin bug based on suitability.

Reproduction: Platymeris Biguttatus reproduce sexually (though in the past it was believed they could also reproduce via parthenogenesis, later shown to be false; although females that have not mated are able to lay eggs, they are infertile). Females instead lay a single egg in the dirt (preferably damp), where over time the egg goes from a brown coloration to a more red-tinted coloration before the "cap" on the egg is taken off by the hatching nymph, which removes itself hind-first; the newly-hatched nymph will have a red coloration similar to the egg, but within about a day this color will harden into a color more consistent with adults of the species.

Image 3 and 4: Platymeris biggutattus egg before and after hatching, as well as newly-born nymphs during the first ~24 hours.

The nymphs have similar hunting and feeding habits to adult members of their species, though only tend to go out when it is necessary and only attempting to attack prey that is slightly bigger than itself. Once a period of time has passed and the nymph has been well-nurtured, it will seek out a secluded area where it will begin its molting phase, whereas after emergence it will stretch its new legs and appendages similarly to when it came out of the egg before again obtaining a darker coloration over a period of about a day until it is a fully-fledged adult. The process of molting and emergence only takes about 20 hours, however.

Research into assassin bug venom: Different scientists have shown a great deal of interest in the venom of different types of assassin bugs, with research showing that some types are able to form two entirely different kinds of venom in distinct glands in their body, which can contain over 100 different types of enzymes and toxins (Walker et. al 2018). Scientists are researching the venom as a possible use in insecticide, which are not only considered eco-friendly due to their adaptation to kill insect tissue only, but are also adaptable themselves, as there is research showing that different types of assassin bugs are able to produce different types of venom depending on their circumstances (harassment and electrostimulation have been shown not only to drive change in venom types, but also higher rates of production of venom overall). The venom is also considered to be a possible avenue into researching how humans perceive pain through different kinds of stimuli found in the bug's venom.

Image 5: artist rendition of Two-Spotted Assassin Bug head and proboscis, where the venom is injected into prey.

https://www.youtube.com/watch?v=-uLGEM7aBWA

Works Cited:

Chłond, D., Bugaj-Nawrocka, A., & Junkiert, Ł. (2015). Current and potential geographical distribution of Platymeris biguttatus (Linnaeus, 1767) with description of nymphs. Zoological Studies, 54(1). doi:10.1186/s40555-014-0092-5

Li, H. (2010). Taxonomic and bionomic notes on the white spot assassin bug Platymeris biguttatus (Linnaeus) (Hemiptera: Reduviidae: Reduviinae). Zootaxa. Retrieved from https://www.researchgate.net/publication/262919168_Taxonomic_and_bionomic_notes_on_the_white_spot_assassin_bug_Platymeris_biguttatus_LinnaeusHemiptera_Reduviidae_Reduviinae.

Walker, A. A., Mayhew, M. L., Jin, J., Herzig, V., Undheim, E. A., Sombke, A., . . . King, G. F. (2018). The assassin bug Pristhesancus plagipennis produces two distinct venoms in separate gland lumens. Nature Communications, 9(1). doi:10.1038/s41467-018-03091-5