Rad Reduviids

Hi Everyone,
    Last week I went to California to do some collecting of Miridae (plant bugs), and when I got back I was busy trying to catch up. But we're back! And today, we're going to talk about Reduviidae, or Assassin Bugs. They are a very diverse group of primarily predators, and come in many different body forms. Here is a nice page of all of the different forms in one group of Reduviidae.

One of the stockier assassin bugs. Image from Wikipedia.com

    Assassin bugs belong to the group Heteroptera, or True Bugs, and have the distinctive piercing mouth parts (the "tube" at the end of their head). They feed by piercing their prey with that tube, injecting digestive chemicals like a needle, and then sucking the juice back out. Yes it sounds brutal, but having a straw-like mouth means they have to live on a liquid diet. Kind of like living off protein shakes your whole life, but only having chemicals to do the job instead of a blender!

Image from http://www.insectsexplained.com/06Hemiptera.htm.

     One of my favorite things about Assassin bugs is that they have different ways of catching prey, with very novel adaptations for whatever they are going after. For example, there are Assassin bugs with thick, strong front-arms for holding down Millipedes, which is the prey of choice for Assassin bugs in the family Ectrichodiinae.

Image taken and copyrighted by Ted C. McRae, whose really great blog is found here

      Other Assassin bugs, like this species here in the video (Acanthaspis petax), cover themselves with the left-over exoskeletons ("skins") of the ants they've already eaten so that they can wander undetected on the nest. Ants primarily use chemo sensory information ("scent") to determine what is friend versus foe, so by covering themselves with the bodies of ants they can then "smell" like ants, and hide among their prey.

     One of the ways that Assassin bugs can stick the ants on their body is by using resin. This is either produced by resin glands on their body, or its spread on from other sources. One group of Assassin bugs, the Bee Assassins, use resin from other sources that they coat their legs with to catch bees flying by. Here is a video of a female one spreading some resin on her legs to get them nice and sticky (many Assassin bugs have very hairy front legs for that reason: more surface area for the resin to attach, and the more sticky they become!).

      Assassin bugs that don't use resin or other sticky traps to catch their prey have other neat ways to catch prey. The group Emesinae, or Thread-legged Bugs, capture prey by stealing it off of spider webs before the spiders can get to it. Their extra thin bodies that look like tiny threads (hence the name!) are light enough that they can step on the webs without getting caught or breaking it. Here is a photo of a larger one from my trip to Costa Rica. You can see how delicate they are compared to the other thick, stout Assassin bugs.

    One of the most commonly found Assassin Bugs and the most striking is the Wheel Bug. Nobody knows for sure why it has the wheel-shaped structure on its thorax (middle part of the body), but it gives a unique form that looks like half of a wheel. The website where I got this really neat image has some videos of these bugs capturing prey and feeding, so I encourage you to check it out here.

Image by and copyrighted for Jim McCormac, from website http://jimmccormac.blogspot.com/2009/08/wheel-bug-attacks-kills.html

        I could go on and on about all the neat habits and body forms of Assassin bugs, but I wanted to wrap up on one of the most famous members, the Kissing Bug. This Assassin bug, which is part of a group that evolved to feed on mammal blood, can transmit the dangerous disease, Chagas, to humans. These sometimes brightly colored and rather large Assassin bugs have taken advantage of stealth maneuvers. During the day they live in cracks and other spaces in houses, waiting. At night, however, they quietly sneak out and look for mammals, including humans and their pets, and quietly sneak up to feed on blood without you noticing. You don't run into these bugs very often in the United States (so don't worry too much!), but they do occasionally occur in some Southern States. There are several research groups working on this special group of Assassin bugs partly because they have this disease-transmitting ability, so they may not be a problem for us much longer.

Triatoma infestans. Image from http://www.servidorpublico.net/noticias/2006/06/09/brasil-elimina-transmissao-da-doenca-de-chagas-pelo-triatoma-infestans.

    So as you can see, Assassin bugs are really neat insects. Next time you head out and investigate your natural environment, look for these unique little predators and take a closer look at the Lions of the bug world.
    Have a great week!