Arthropod Roundup: Callinectes in the UK, horny females, artificial arthropod hair, and genetic mosquito control

Brief blurbs about recent arthropod news and research:

• The blue crab, Callinectes sapidus, has been found in England for the second time ever. These ill-tempered, but delicious, swimming crabs are native to North America; where they represent a major marine fishery despite serious conservation concerns. Previously, blue crabs have turned up in Japan and the Mediterranean. It is conventionally thought that these crabs were brought in as larvae in ship ballast water and have since gained a foothold in their new homes. It is possible that this blue crab in Cornwall also came over from America in ballast water, or it could have been carried on ocean currents up from the Mediterranean population. It is unclear weather this is an isolated individual or a representative of a new invasive population.
• You will be disappointed to learn that the horny females I referred to in the title are dung beetles. One usually associates the growth of horns and antlers with males who use them to battle for dominance in a social hierarchy or for their pick of the choicest females. However, female dung beetles, Onthophagus sagittarius, are known to have much more impressive horns than their male counterparts. A new study suggests that these horns are used by the females to compete over reproductive resources (i.e. poop). Size matched females with larger horns were found to achieve greater reproductive fitness, making horn size a positively selected female secondary sex characteristic in these beetles. (Via 80Beats)
  
  

  Horned Onthophagus sagittarius females square off. Photo: Sean Stankowski

• New research reports the development of synthetic superhydrophobic materials inspired by tiny, water repellent hairs in insects. These hairs are found on the legs of water walkers and the backs of Stenocarid beetles, which use the hairs to channel water droplets to their mouth.
• The genomes of the malaria mosquito, Anopheles gambiae, and the yellow fever mosquito, Aedes aegypti, were published in 2002 and 2006, respectively. These sequencing efforts appear to be bearing a lot of fruit as of late; as several genetic approaches to controlling the spread of mosquito vectored diseases have been proposed. These include; increasing the immunity of mosquitoes to the dengue fever virus, weakening mosquitoes by preventing waste secretion, and preventing female mosquitoes from developing functioning flight structures. Some of these ideas are pretty far from real-world application unfortunately, and the buzz surrounding them seems to be the result of overly-excitable university PR departments.

The Chesapeake Bay’s declining bumper crab

As a Baltimore resident, it was only a matter of time before I talked about our most popular and ill-tempered local crustacean. The blue crab, Callinectes sapidus (savory beautiful swimmer), is a Portunid (swimming) crab found along the Western Atlantic coast, from Nova Scotia to Argentina. They have also been introduced to the Pacific coast of Central America, Europe, and Asia. They have a complex, migratory life-cycle that takes them between estuaries and the open ocean. Blue crabs are harvested for food in the US and play an integral part in coastal economies, especially within the Chesapeake Bay where they are somewhat of a cultural icon.

Unfortunately, the population and harvest of C. sapidus has been in sharp decline since the early 1990s due to over-fishing, development, and agricultural runoff. Pollution in the bay unbalances the ecosystem, resulting in harmful microorganism blooms, and stresses the crabs, making them more susceptible to bacterial and viral infections. Due to the economic impact of declining harvests, a variety of regulations and research directives have been employed in order to rejuvenate the blue crab population.