Human body lice diverged from their head inhabiting kin when fabric and fur replaced bare skin as the predominant fashion.
First, as promised: Winners of the 2016 Bug of the Week Academy Awards
Last week was fun and games at the. Bug of the Week thanks the members of the Bug of the Week Academy for selecting this year’s winners.
In the category “GLAD THEY ARE TINY” the runaway winner was the lycosid wolf spider in ““Wolves on a summer’s night” for her stunning vampire-like performance as the exsanguinator of crickets.
In the category "YOU OUGHT TO BE IN PICTURES" a close race was won by dame Danaus plexippus in the role of a peripatetic vagabond who braves lethal predators, crazed New England drivers, and horrific weather on a three thousand mile journey to her winter home in Mexico in “Monarchs and Mojitos.”
In the category "MORE THAN I NEEDED TO KNOW" the tiny black fly pulled an upset for her sanguine performance in “There will be blood.”
Congratulations to this year’s stand-out winners!
Lousy times
Scores of lice eggs, a.k.a nits, can be found in clothing of those infested with body lice.
A few weeks ago we visited yellow fever mosquitoes and the Zika virus. This week we turn our attention to another blood sucker in the news. Human head lice have been making headlines in recent weeks owing to the discovery that infestations of these unpleasant buggers may be on the rise. As a child growing up in rural New Jersey, the first day back to elementary school was punctuated with a distressing trip to the school nurse for the annual head louse inspection. In my school the nurse was a formidable woman with very large hands, a deep voice, and the aroma of a hint of disinfectant. She would plunge her finger tips into each child’s scalp in search of nits, the tiny white eggs of the head louse. Nits are deposited by the female head louse, who firmly glues the eggs to hairs with a proteinaceous glandular secretion. Eggs hatch into tiny nymphs with needle-like mouthparts that are inserted into the skin to imbibe protein rich blood coursing through capillaries below the surface. Nymphs shed their skin several times before developing into blood thirsty adults that breed within the hirsute forest.
For boys in my household, detection of nits or head lice earned a marine-style haircut when Dad arrived home that evening. Girls were treated a tad better but had to endure several lindane shampoos to rid themselves of these ectoparasites. With modern advances in insecticide chemistry lindane was supplanted by natural and synthetic derivatives of the botanical insecticides known as pyrethrins. Pyrethrins and their chemical children, called synthetic pyrethroids, disrupt normal nerve function in insects.
So, why are head lice on the rise? In a recent study, scientists at the University of Massachusetts and their colleagues discovered that head lice carried genes for resistance to pyrethrins and permethrin-based insecticides in more than 99% of humans sampled. This sample was robust in that 115 subjects from 18 geographical locations in 12 U.S. states provided head lice for the study. Samples of head lice from several locations in Canada revealed high levels of insecticide resistance as well. One disturbing trend discovered in the study was the mutation conferring insecticide resistance had increased dramatically in the U.S. in samples of lice collected between 1999 and 2008. The widespread use of popular pyrethrins and pyrethroids appear to have selected for highly resistant “super lice” that are very difficult to control with these insecticides. Fortunately, alternative chemistries are available to combat these tiny vampires.