Geographic Variation of Photoperiodic Diapause but Not Adult Survival or Reproduction of the Invasive MosquitoAedes albopictus(Diptera: Culicidae) in North America

Abstract

Climate differences across latitude can result in seasonal constraints and selection on life-history characters. Because Aedes albopictus (Skuse) invaded North America in the mid-1980s, it has spread across a range of ≈14° latitude and populations in the north experience complete adult mortality because of cold winter temperatures that are absent in the south. Life-table experiments were conducted to test for differences in the adult survival and reproductive schedules of Ae. albopictus females from three populations from the northern (Salem, NJ; Springfield, IL; Eureka, MO; ≈39° N) and southern (Palm Beach, Palmetto, Tampa, FL; ≈27–28° N) extremes of the species distribution in North America. There were consistent differences between northern and southern populations in incidence of photoperiodically-induced egg diapause. Under short daylength, diapause eggs constituted twice the proportion of total viable eggs from northern females (81.9–92.1%) than southern females (35.9–42.7%). There were no consistent differences between northern and southern populations in resource allocation between reproduction and maintenance, reproduction over time, and reproductive investment among offspring, and no apparent trade-offs between diapause incidence with reproduction or longevity. Our results suggest that the main response of North American Ae. albopictus to unfavorable winter climates is via the life history strategy of producing diapausing eggs, rather than quantitative variation in reproduction, and that there are no detectable costs to adult survival. Inherent geographic variation in the expression of diapause, consistent with the latitudinal extremes of A. albopictus, indicates evolutionary loss of diapause response in southern populations because of the invasion of A. albopictus in North America.

Latitudinal clines: an evolutionary view on biological rhythms,

“…The latitudinal cline in CPP (figure 3a) leads to the prediction that the proportion of diapausing individuals increases with latitude. This general trend has been found in many species [8,12,[31][32][33][34]. In some cases, populations at high latitudes evolved obligate diapause where all individuals enter diapause at a certain stage regardless of environmental conditions [35].…”

Use of Light Traps and Differing Light Color to Investigate Seasonal Abundance of the Date Palm Pest, <I>Oryctes agamemnon arabicus</I> (Coleoptera: Scarabaeidae)

“…Accordingly, O. agamemnon arabicus adult numbers started to increase in response to an increase in the photoperiod until the population reached a peak and started to decline when the photoperiod became shorter. Leisnham et al (2011) reported photoperiod as a factor affecting inter-population differentiation in the survival and diapause of Aedes albopictus (Skuse) (Diptera: Culicidae). Exposure to short photoperiods during the early adult stage was necessary to induce diapause in 50% of the population of Orius insidiosus (Say) (Heteroptera: Anthocoridae), and the short photoperiod served to maintain diapause in adult females (Ruberson et al 2000).…”

Photoperiodic Diapause and the Establishment ofAedes albopictus(Diptera: Culicidae) in North America

“…Substantial evidence indicates that multiple aspects of the diapause response have contributed to climatic adaptation of Ae. albopictus across its range in North America (Hawley et al 1989;Lounibos et al 2003Lounibos et al , 2011Leisnham et al 2011;Urbanski et al 2012). Further studies of diapause ecology, especially studies focusing on diapause induction and termination of diapause in natural populations and geographic variation of traits expressed during diapause will be especially important.…”