The molecular basis of increased desiccation resistance during diapause in the Asian tiger mosquito, Aedes albopictus

Department of Biology, Georgetown University, 37th and O Sts. NW, Washington, DC 20057, USA.
Proceedings of the Royal Society B: Biological Sciences (Impact Factor: 5.05). 09/2010; 277(1694):2683-92. DOI: 10.1098/rspb.2010.0362
Source: PubMed


Photoperiodic diapause is a crucial adaptation to seasonal environmental variation in a wide range of arthropods, but relatively little is known regarding the molecular basis of this important trait. In temperate populations of the mosquito Aedes albopictus, exposure to short-day (SD) lengths causes the female to produce diapause eggs. Tropical populations do not undergo a photoperiodic diapause. We identified a fatty acyl coA elongase transcript that is more abundant under SD versus long-day (LD) photoperiods in mature oocyte tissue of replicate temperate, but not tropical, A. albopictus populations. Fatty acyl CoA elongases are involved in the synthesis of long chain fatty acids (hydrocarbon precursors). Diapause eggs from a temperate population had one-third more surface hydrocarbons and one-half the water loss rates of non-diapause eggs. Eggs from a tropical population reared under SD and LD photoperiods did not differ in surface hydrocarbon abundance or water loss rates. In both a temperate and tropical population, composition of hydrocarbon chain lengths did not differ between eggs from SD versus LD conditions. These results implicate the expression of fatty acyl coA elongase and changes in quantity, but not composition, of egg surface hydrocarbons as important components of increased desiccation resistance during diapause in A. albopictus.

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    • "The worldwide trades in secondhand tires and lucky bamboo, both of which often contain standing water making them ideal places for mosquito eggs and larvae, have been key factors in Ae. albopictus transportation. Once established in a new region, the tiger mosquito easily adapts and persists in a wide range of habitats, even in temperate climates mainly due to its aptitude to enter into a state of dormancy or " diapause " (Urbanski et al., 2010). Undoubtedly, the intrinsic capacities of the mosquito populations largely play an important role in their ecological plasticity. "
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    • "It is unclear how these interspecific observations could be verified inside a species. No modulation of desiccation resistance was observed in eggs of a tropical strain of Kuala Lumpur, Malaysia, reared under different photoperiodic conditions (Urbanski et al., 2010a). Photoperiodic rearing conditions don't modify maternal wing length; consequently we dismiss a possible indirect effect of maternal size on eggs volume. "
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