Bees Collect DDT

Biological Strategy

Bees

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Protect From Chemicals

Chemicals are everywhere in the bodies of living organisms and their external environments. While most chemicals are valuable or benign, some are toxic, including those used for defense (such as the mucus that protects clownfish from an anemone’s stinging tentacles). Even naturally-occurring chemicals, such as arsenic, must be managed to reduce their impact. Some living systems have strategies to break down harmful chemicals, alter them into less toxic forms, physically prevent chemicals from harming sensitive tissues, and more. For example, some herbivorous mammals can digest toxic compounds in plants because they have a particular enzyme that helps them process poisonous plant compounds.

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Chemically Break Down Organic Compounds

The vast majority of biochemical assembly and breakdown processes–even by the most complex organisms–occur within cells. In fact, cells are able to perform hundreds, even thousands of chemical transformations at the same time under life-friendly conditions (ambient temperature and pressure in an aqueous environment). Part of the reason that decomposition reactions (chemical breakdown) can occur under such mild conditions is because most often, they occur in a stepwise, enzyme-mediated fashion, sipping or releasing small amounts of energy at each step. For example, the breakdown of glucose to pyruvate–and the release of energy–occurs in the 10-step enzyme catalyzed process of glycolysis.

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Insects

Class Insecta (“an insect”): Flies, ants, beetles, cockroaches, fleas, dragonflies

Insects are the most abundant arthropods—they make up 90% of the animals in the phylum. They’re found everywhere on earth except the deep ocean, and scientists estimate there are millions of insects not yet described. Most live on land, but many live in freshwater or saltwater marshes for part of their life cycles. Insects have three distinct body sections: a head, which has specialized mouthparts, a thorax, which has jointed legs, and an abdomen. They have well-developed nervous and sensory systems, and are the only invertebrate that can fly, thanks to their lightweight exoskeletons and small size.

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Some orchid bees are able to tolerate high concentrations of DDT, strategy unknown.

“While studying the ecology of the malaria vector Anopheles
(Nyssorhynchus) darlingi Root along the Ituxi River, Amazonas, Brazil,
we observed aggregates of bees on the walls of houses that were
routinely sprayed with DDT. Several bees collected from DDT-treated
house walls in August 1978 were identified as male specimens of
Eufriesia purpurata (Moscary) of the tribe Euglossini (Hymenoptera:
Apoidae)…These bees
were well known to the local residents as the insects that eat DDT and
we present here the first documentation that they (1) are attracted to
DDT, (2) actively collect large quantities of DDT from treated house
walls and (3) suffer no apparent insecticidal effects. We also found
that the frequency of house visiting is most intense during July to
September. Most bees arrive at houses before 12.00 h, remain 2−3 h and
return on subsequent days to collect more DDT.” (Roberts et al. 1982:62)

“Brazilian bees of the species Eufriesea purpurata are known to
tolerate very high concentrations of DDT. As reported in the literature,
these bees have suffered no harm from as much as 2 mg/bee, which is in
the per-cent range of the body weight. In 1979, individuals of E.
purpurata were captured as they collected DDT from walls of
remote, rural houses in Brazil. Reported herein are quantities and
identities of DDT, DDT metabolites, and other organohalogen compounds in
four samples of bees stored since 1979. The concentrations of DDT (sum
of p,p′-DDT, -DDE, and -DDD) ranged from 23 to 314 μg/bee
which is up to twelve fold higher than the LD₅₀ value of DDT
in the honey bee (Apis mellifera) but significantly lower than
the no-effect concentration in E. purpurata.
Enantioselective determination confirmed the presence of racemic o,p′-DDT
in the four individual samples. GC/ECNI-MS investigation resulted in
the detection of low amounts (< 1 μg/bee) of PCA, lindane, and
chlordane. At higher retention times four unknown compounds were
detected with a proposed molecular ion at m/z 498, a
non-aromatic hydrocarbon backbone along with the presence of eight
chlorine substituents. Neither the structure nor the origin of these
compounds could be determined. Considering where and when the bees were
collected and considering the biology and ecology of the euglossine bees
themselves, we propose that the four unknowns are natural products and,
as such, are the most highly chlorinated natural compounds yet
discovered.” (Vetter & Roberts 2007:371)

http://www.nature.com/nature/journal/v297/n5861/abs/297062a0.html
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V78-4NBR3PM-5&_user=10&_coverDate=05%2F15%2F2007&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docancho