The objective of this paper is to disentangle the effects of photoperiod and diapause Ganetespib purchase on egg size and embryonic developmental time in A.albopictus. We predict that diapause induction in A. albopictus eggs will generate a
prolonged embryo development sometime before the diapausing initiation. To test this prediction, we will investigate the effects of photoperiod and of the diapause syndrome by recording the size of eggs as related to an indicator of mother size (maternal wingspan), and by hourly monitoring the appearance of four features representing successive steps in the embryo development. The simultaneous study of a diapausing temperate strain and a non-diapausing tropical strain under long and short daylengths will allow us to disentangle the effects on development of the daylength experienced by the mother. The animal facility of the “Entente Interdépartementale Selleck PD-332991 pour la Démoustication du littoral méditerranéen” has received accreditation from the French Ministry of Agriculture to perform experiments on live guinea pig
(permit number B34-172-29) in appliance of the French and European regulations on care and protection of Laboratory Animals. Two strains of A.albopictus were used in this study. The European temperate strain named SPAM was collected in 2007 in the coastal area of Nice, France (43° 41′ 45″ N, 7° 16′ 17″ E). The tropical strain is native of La Reunion Island, located south-east of Africa near the Madagascar island, and was collected in 2011 in the coastal area of Saint-Denis Providence city (20° 52′ 44″ S, 55° 26′ 53″ E). The F16-F17 Pyruvate dehydrogenase and F2-F3 maternal generations were used respectively for the temperate and tropical strains. Mosquitoes of both strains were maintained in a laboratory room under a constant environment of 21.5 ± 0.3 °C, 80.1 ± 2.4% relative humidity, a photoperiod of 16 h of light and 8 h of darkness. Larvae were reared in batches of 500 larvae per pan (30.5 × 20 × 6 cm) in 2 l tap water and fed with 3.5 g of milled dog food during larvae development. This standardized
protocol was chosen to produce an optimal expression of photoperiodic response, as it has been shown that this response is sensitive to temperature and larval diet (Pumpuni et al., 1992). After pupation, 500 pupae were placed per pan and transferred in cages in photoperiodic chambers. They were either submitted to non-diapausing long-days conditions (LD) with a light:dark cycle of 16 h:8 h, or short-days conditions (SD) inducing diapause in temperate strain with a light:dark cycle of 9 h:15 h. Photoperiodic chambers consisted of windowless plastic boxes (65 × 65 × 40 cm) with a zipper opening in black-cloth placed in the rearing room. Individual chambers were maintained at a constant temperature of 21.5 ± 0.4 °C and 79.1 ± 2.3% relative humidity, using a fan-produced air flow and a periodic air dampening system made of a water pot stirred using an aquarium air-pump.