Discovering amazing arthropods
Arthropods (insects, spiders and their relatives) are beautiful, diverse, and exhibit fascinating life history strategies. They are everywhere: hiding in leaf-litter, feeding on our blood, mining plant tissues. Broadly defined, the "Arthropoda" are invertebrate animals with an exoskeleton, a segmented body, and paired, jointed appendages. The latter is the byline for this new blog with SciLogs - Expiscor.
Many legs, many stories.
Ever since I can remember, I've been curious about the natural world and I want to share my curiosity and passion with you. I'm now living a dream - working as a Professor and studying arachnology, entomology and ecology on a daily basis. I will rework the most interesting stories that I stumble across and bring them to you each week. The stories will mostly be from things I know about - the world of arthropods (although I will occasionally highlight stories from other wonders of the natural world). I will try to ensure these stories are not fiction: they will be based in research and will be factual (I count on my readers to keep me honest).
Let's get started with three short stories:
1) Pranburia mahannopi - a splendid ant mimic (look carefully! It's a spider).
This photograph came to me via Crystal Ernst, and from there, eventually showed up on Why Evolution is True. This species was photographed by Arthur Anker (in Cambodia), and is labelled as P. mahannopi, a known ant-mimic. Spiders are really very good mimics of ants, and those with a physical resemblance are known as myrmecomophs. The most likely and accepted explanation for this mimicry is that most myrmecomorphs are so adapted for predator avoidance (i.e., few things eat ants, so spiders can 'hide' with ants if they look like them). Paula Cushing wrote an excellent piece about this mimicry (and an update here) but despite a good inventory (and photos!) of spider ant-mimics, I would argue there are not nearly enough detailed natural history studies on the topic.
2) Piagetiella peralis - a gruesome parasite.
Lice are tremendous animals - affecting major events in human history, and causing stress for school kids around the world. Now, imagine lice IN your mouth... that's the situation with the 'pouch lice' found in the mouths of pelicans. These animals chew away on the soft tissues of pelicans, causing inflammation and bleeding, as was documented by Dik (2006). Ouch.
Wayne Knee forwarded this SEM image of Piagetiella peralis and I'll share it with you here:
3) Micromalthus debilis - an astonishing life cycle.
I'm not even sure I can explain this beetle's life cycle. So let me rely on David Maddison's explanation: It lives in rotting wood, and most specimens one finds in the wood are all females, and are larviform, either larvae or are developed enough that they can reproduce but look like larvae. Mature female "larvae" generally give birth to living larvae (without laying eggs); these young larvae are active, and with legs, and are called a "triungulin". A triungulin moults into legless female larva, which can then develop either into (1) a pupa that then emerges as awinged adult, (2) a larviform female that will itself will give birth to triungulins, (3) a larviform female that lays a single male egg that hatched into a larva that eats its mother, (4) a larviform female that can reproduce in both of the latter ways.
That is pretty stunning! ...And even more details can be found in Pollock & Normark (2002).
Even better, how about a drawing, this from Ainsley Seago:
These three short stories hopefully illustrate the amazing life histories and biology of our segmented friends. This is just the beginning... I hope you continue to stop by and explore biodiversity with me.
Cushing, P. (1997). Myrmecomorphy and myrmecophily in spiders: a review The Florida Entomologist, 80, 165-193 DOI: 10.2307/3495552
Cushing, P. (2012). Spider-Ant Associations: An Updated Review of Myrmecomorphy, Myrmecophily, and Myrmecophagy in Spiders Pysche DOI: 10.1155/2012/151989
Dik, B. (2006). Erosive Stomatitis in a white pelican (Pelecanus onocrotalus) caused by Piagetiella titan (Mallophaga: Menoponidae). Journal of Veterinary Medicine, Series B DOI: 10.1111/j.1439-0450.2006.00927.x
Pollock, D. A. and B. B. Normark. 2002. The life cycle of Micromalthus debilis LeConte (1878) (Coleoptera: Archostemata: Micromalthidae): Historical review and evolutionary perspective. Journal of Zoological Systematics and Evolutionary Research 40(2):105-112. http://onlinelibrary.wiley.com/doi/10.1046/j.1439-0469.2002.00183.x/abstract