Diapause in the Boll Weevil, Anthonontus grandis Boheman, As Related to Fruiting Activity in the Cotton Plant

Studies in Arkansas show that boll weevil diapause is related to changes in fruiting activity of the cotton plant. Generally, when larval development took place while fruiting levels were increasing or being held at a high level, diapause in resulting adults was low (0-20%). Diapause was approximately 20-50% when larval development coincided with decreasing fruiting levels, and was 50-100% as true cut-out approached. Regrowth cotton generally lowered diapause incidence and as fruiting levels decreased, diapause increased. Therefore, the boll weevil not only responds to short photoperiods that are characteristic during the fall in the temperate zone, but also may respond throughout the season to changes in fruiting activity of the cotton plant

Some Effects of Photoperiod and Cold Storage on Oviposition of the Cereal Leaf Beetle Oulema Melanopus (Coleptera: Chrysomelidae)

An expanded program of research on the cereal leaf beetle, Oulema melanopus (L.), in various north-central states has made it necessary to develop methods of rearing all stages of the beetle for laboratory use. Because the insect survives diapause in the adult state (Castro, 1964 and Connin, et al., 1968) it must presently be stored 10-12 weeks at 38 F before consistent oviposition is obtained. Hoopingarner, et al. \u27(1965) indicated that, while males are sexually mature in the prediapause condition, the female was unwilling to mate until after diapause and was not mature sexually until after mating. More recent work by Bowers and Blickenstaff (1966) and Connin et al. (1967) indicated the possibility of breaking or eliminating diapause with chemicals. However, photoperiod also seemed influential in terminating diapause after varying periods of cold storage. The present paper reports observations on the photoperiodic effects

Two Trapping Systems to Determine Incidence and Duration of Migration of Adult Alfalfa Weevils, \u3ci\u3eHypera Postica\u3c/i\u3e (Coleoptera: Curculionidae)

Emergence and flight traps were used to study the pre- and post-diapause movements of the alfalfa weevil, Hypera postica. The emergence traps proved to be an excellent tool in determining the time of diapause termination and in providing an accurate accounting of the number of weevils per unit area in aestivation sites. The flight traps showed when diapause flights to and from alfalfa fields took place. Both trapping systems can be utilized in a pest control program to locate more closely where the alfalfa weevil aestivates and when diapause related movements occur

Photoperiodic Response of Abrostola asclepiadis (Lepidoptera: Noctuidae), a Candidate Biological Control Agent for Swallow-worts (Vincetoxicum, Apocynaceae)

A biological control program is in development for two swallow-wort species (Vincetoxicum, Apocynaceae), European vines introduced into northeastern North America. One candidate agent is the defoliator Abrostola asclepiadis (Denis and Schiffermüller) (Lepidoptera: Noctuidae). The moth reportedly has up to two generations in parts of its native range. We assessed the potential multivoltinism of Russian and French populations of the moth by rearing them under constant and changing photoperiods, ranging from 13:11 to 16:8 hour (L:D). The French population was also reared outdoors under naturally-changing day lengths at a latitude similar to northern New York State. Less than six adult moths emerged, with one exception, for any photoperiod treatment. We expect A. asclepiadis to be univoltine if it were to be released into North America, limiting its potential impact on swallow-worts. It should therefore be given a lower priority for release

Summer Diapause of the Clover Leaf Weevil, \u3ci\u3eHypera Punctata,\u3c/i\u3e and Lesser Clover Leaf Weevil, \u3ci\u3eHypera Nigrirostris,\u3c/i\u3e in Wisconsin

Low respiration rates, immobility, lack of feeding, and undeveloped reproductive systems confirmed a summer diapause in the overwintered and current-year adults of the clover leaf weevil, Hypera punctata, and lesser clover leaf weevil, Hypera nigrirostris. The prolonged summer diapause and extended winters in Wisconsin set strict limitations on the available time for damaging populations to develop on red clover, Trifolium pratense thus assuring the status of these weevils as minor pests

Diapause and Emergence Patterns in Univoltine and Bivol Tine Populations of Promethea (Lepidoptera: Saturniidae)

Data are presented on the diapause and the seasonal emergence patterns of the adults of a univoltine Callosamia promethea population from northern Indiana and a partially bivoltine population from central Illinois. At Urbana, Illinois, the median emergence date of adults from overwintering Illinois pupae was about a month earlier than that of adults from overwintering Indiana pupae. Illinois samples had a much longer emergence period than Indiana samples. Indiana samples showed a slight tendency toward a bimodal emergence pattern, a few individuals emerging in late May and the rest emerging as a tightly synchronized group from late June to mid-July. Early emerging lIIinois moths produced mostly non.diapausing progeny, but the proportion of diapausing progeny increased as the season progressed. Some females produced both diapausing and non· diapausing progeny. Adults from non-diapausing pupae from early August to early September

Effect of Selecting Cereal Leaf Beetle (Coleoptera: Chrysomelidae) Males by Age and Feeding Behavior on Nondiapause Progeny

In a nondiapause culture of cereal leaf beetles, Oulema melanopus (Coleoptera: Chrysomelidae), females ovipositing within 20 days after emergence were considered nondiapause. However, sexually active males in the same generation could be nondiapause or prediapause. Changes in the nondiapause incidence were compared between progenies from\u3e 15 day old males that were feeding actively and photopositive (considered \u27nondiapause\u27 males) and progenies from younger males (nonselected males). Nondiapause females increased by 19% (n = 35 generations) and decreased 22% (n 31 generations) in the progenies of \u27nondiapause\u27 and nonselected males, respectively, suggesting that nondiapause males were selected in the former group, but prediapause males in the latter group substantially decreased nondiapause. In one generation, 14 progenies from individual pairs ranged from 21 to 100% nondiapause females, indicating that each sex in each parental pair was nondiapause, but nondiapause was incompletely expressed in most of the progenies. The percentage of \u27nondiapause\u27 males was not significantly different than, and was strongly correlated to the percentage of nondiapause females of the same generation, indicating that nondiapause was not sex-linked, and that selecting males by age and behavior decreased the probability of dilution of nondiapause by prediapause males

Large-Scale Modelling of the Environmentally-Driven Population Dynamics of Temperate Aedes albopictus (Skuse)

The Asian tiger mosquito, Aedes albopictus, is a highly invasive vector species. It is a proven vector of dengue and chikungunya viruses, with the potential to host a further 24 arboviruses. It has recently expanded its geographical range, threatening many countries in the Middle East, Mediterranean, Europe and North America. Here, we investigate the theoretical limitations of its range expansion by developing an environmentally-driven mathematical model of its population dynamics. We focus on the temperate strain of Ae. albopictus and compile a comprehensive literature-based database of physiological parameters. As a novel approach, we link its population dynamics to globally-available environmental datasets by performing inference on all parameters. We adopt a Bayesian approach using experimental data as prior knowledge and the surveillance dataset of Emilia-Romagna, Italy, as evidence. The model accounts for temperature, precipitation, human population density and photoperiod as the main environmental drivers, and, in addition, incorporates the mechanism of diapause and a simple breeding site model. The model demonstrates high predictive skill over the reference region and beyond, confirming most of the current reports of vector presence in Europe. One of the main hypotheses derived from the model is the survival of Ae. albopictus populations through harsh winter conditions. The model, constrained by the environmental datasets, requires that either diapausing eggs or adult vectors have increased cold resistance. The model also suggests that temperature and photoperiod control diapause initiation and termination differentially. We demonstrate that it is possible to account for unobserved properties and constraints, such as differences between laboratory and field conditions, to derive reliable inferences on the environmental dependence of Ae. albopictus populations