In high-altitude summer pastures, horseflies (Diptera: Tabanidae) can be a serious nuisance to livestock, as well as mechanical vectors of animal diseases such as besnoitiosis, an enzootic disease in the Pyrenees. However, the activity of horseflies in mountainous environments is poorly documented. To study the seasonality and distribution of tabanids in the Pyrenees Mountains, a sampling design was set up in two valleys on opposite sides of the mountain, one north-facing and one south-facing, along high-elevation gradients and at different distances from a water body between May and October 2011. The influence of the landscape on species richness and abundance was assessed by taking into account forested and unforested areas in 200 m radii around the trapping sites. Our findings indicated that: (1) The slope, the altitude and the size of unforested patches significantly influenced community composition of tabanids. (2) Altitude had a positive or a negative effect, depending on the species. (3) Species richness and abundance were negatively correlated with large open habitats and positively correlated with patch-shape complexity. (4) Seasonal succession of the most abundant species was observed in both valleys, with a maximum of catches at the beginning of August; however, tabanid activity ended earlier in the southern valley, which was more exposed to sunlight. (5) Philipomyia aprica, Tabanus bromius, Tabanus glaucopis and Hybomitra auripila were active from 9:00 to 19:00 h (GMT+1), with a peak of activity at midday. This paper also discusses the implications of these findings in relation to changes in horsefly distribution and their control in mountainous environments.

The intensity of pupal diapause in the cotton bollworm, Helicoverpa armigera (Hübner) was investigated under both laboratory and natural conditions. By transferring diapausing pupae induced under LD 11:13, LD 12:12 and LD 13:11 at 20, 22 and 25 °C to 25 °C combined with LD 15:9 to terminate diapause the rearing day length of 11 h evoked greater intensity of diapause than did 12 and 13 h at 25 °C; whereas the rearing temperature of 25 °C evoked more intense diapause than did 20 and 22 °C under LD 11:13. By transferring diapausing pupae induced under LD 12:12 at 20 and 22 °C to six temperatures of 18, 20, 22, 25, 28 and 31 °C combined with LD 15:9 to terminate diapause, the duration of diapause was significantly shortened from 146 days at 18 °C to 24 days at 31 °C, showing that high temperatures significantly accelerate diapause development. Furthermore, the duration of diapause was significantly longer at the rearing temperature of 22 °C than that at 20 °C when the diapause-terminating temperatures were 20 and 22 °C. Chilling at 5 °C did not shorten the duration of diapause but lengthened it when chilling period was included. However, chilling plays an important role in synchronizing adult emergence. Rearing temperature of 22 °C also evoked more intense diapause than did 20 °C in most chilling treatments. When the overwintering pupae were transferred at different times from natural temperatures to 25 °C, it was found that the earlier the transfer took place, the earlier the adults emerged when the time spent under natural conditions was included. However, cool temperatures before March showed an enhanced effect on diapause development at 20 °C, suggesting that the high diapause-terminating temperature can offset the effect of chilling on diapause development. The result of diapause termination under natural conditions suggests that the developmental threshold for post-diapause development in H. armigera should be around 17.5 °C.

Haemaphysalis longicornis (Acari: Ixodidae) is one of the most common and important arthropod disease vectors in Japan, carrying Japanese spotted fever and bovine theileriosis. The recent expansion of sika deer (Cervus nippon, Artiodactyla: Cervidae) populations, the most common wild host of H. longicornis, has also caused concern about increasing the risk of vector-borne diseases in Japan. We used generalized linear mixed model analysis to determine the relative contribution of deer density and other biological and abiotic factors on the abundance of H. longicornis ticks questing at each developmental stage. A total of 6223 H. longicornis adults, nymphs, and larvae were collected from 70 sites in three regions of central Japan. The abundance of questing adult and nymphal ticks was associated with deer density and other biotic and abiotic factors. However, the abundance of questing larvae showed no association with deer density but did show an association with other biotic and abiotic factors. These findings show that a high density of deer along with other biotic and abiotic factors is associated with increased risk of vector-borne diseases through amplified local abundance of questing nymphal and adult H. longicornis. Further, questing larvae abundance is likely regulated by environmental conditions and is likely correlated with survival potential or the distribution of other host species.

Young workers, experimentally removed from their nest and set in front of it, are not very good at finding the nest entrance and entering the nest. I examined how young ants learn their nest entrance characteristics, dealing only with the entrance sensu stricto, not with its vicinity. I observed that young ants have the innate behavior of trying to exit and re-enter their nest. I found that they are imprinted with the nest entrance odor while they are still living inside their nest and that they learn the visual aspect of their nest entrances, thanks to operant conditioning, when they exit their nest and succeed in re-entering in the course of their first short trips outside.

Musca domestica L. (Diptera: Muscidae) is a vector of a range variety of pathogens infecting humans and animals. During a year, housefly experiences serial population bottlenecks resulted in reduction of genetic diversity. Population structure has also been subjected to different selection regimes created by insect control programs and pest management. Both environmental and genetic disturbances can affect developmental stability, which is often reflected in morphological traits as asymmetry. Since developmental stability is of great adaptive importance, the aim of this study was to examine fluctuating asymmetry (FA), as a measure of developmental instability, in both wild populations and laboratory colonies of M. domestica. The amount and pattern of wing shape FA was compared among samples within each of two groups (laboratory and wild) and between groups. Firstly, the amount of FA does not differ significantly among samples within the group and neither does it differ between groups. Regarding the mean shape of FA, contrary to non-significant difference within the wild population group and among some colonies, the significant difference between groups was found. These results suggest that the laboratory colonies and wild samples differ in buffering mechanisms to perturbations during development. Hence, inbreeding and stochastic processes, mechanisms dominating in the laboratory-bred samples contributed to significant changes in FA of wing shape. Secondly, general patterns of left–right displacements of landmarks across both studied sample groups are consistent. Observed consistent direction of FA implies high degrees of wing integration. Thus, our findings shed light on developmental buffering processes important for population persistence in the environmental change and genetic stress influence on M. domestica.

Spalgis epius and Cryptolaemus montrouzieri are the two potential predators of different species of mealybugs. However, the mode of their interactions is not known to use these predators together in the field. Hence, we investigated on the possible interactions i.e., cannibalism, intraguild predation (IGP) and competition between the predators in the presence and absence of prey Planococcus citri. In the presence of prey, no cannibalism and predation were observed in both S. epius and C. montrouzieri larvae. A pair of S. epius larvae consumed significantly more number of mealybugs than one S. epius/C. montrouzieri larva or a pair of C. montrouzieri larvae. The predation of S. epius larva by C. montrouzieri larva was significantly more than the predation of C. montrouzieri by S. epius. Conspecific and interspecific egg predation was absent both in S. epius and C. montrouzieri. Cannibalism in C. montrouzieri was more than that in S. epius. The study indicated that C. montrouzieri larvae can be used as an additive along with voracious S. epius larvae under abundant prey population. IGP was asymmetric between the two predators in the absence of prey. Both S. epius and C. montrouzieri larvae can maintain a stable coexistence when prey is abundantly available, however, in the complete absence of prey C. montrouzieri may dominate the guild. This study provides an insight into the possible complex inter- and intraspecific predatory phenomena in the field to use these two predators in the biological control of mealybugs.

Stink bugs (Heteroptera: Pentatomidae), including Nezara viridula (L.), Euschistus servus (Say), and Chinavia hilaris (Say), are economic pests in farmscapes where they move within and between closely associated crop and non-crop habitats. Thus, field edges in these farmscapes include not only crop-to-crop interfaces but also those edges adjoining non-crop habitats. We examined the influence of field edges on colonization of stink bugs in southeastern USA farmscapes composed of typical combinations of corn, peanut, and cotton. For E. servus and N. viridula, egg-to-adult development and presence of both sexes on all crops indicated that the crops served as reproductive plants. Adult C. hilaris were rarely found on corn and on crops associated with it, and they were present mainly in cotton in peanut–cotton farmscapes. Mature crop height was significantly higher for corn than for cotton and significantly higher for cotton over peanut, and an edge effect in dispersal of stink bugs into a crop was detected up to 4.6, 8.2, and 14.6 m from the crop-to-crop interface in corn, cotton, and peanut, respectively. These results suggest that stink bug dispersal into a crop decreases as crop height increases. The first stink bug-infested crop at the crop-to-crop interface was the most significant contributor of colonizing stink bugs to an adjacent crop. An edge effect in dispersal of stink bug adults was detected in corn next to non-woodlands and woodlands and in cotton adjacent to woodlands. Edge effects were never detected in side edges of peanut. Overall, our results indicate that both plant height and host plant suitability can influence edge-mediated dispersal of stink bugs at field edges.

In this study, we use DNA barcodes for species delimitation to solve taxonomic conflicts in 86 specimens of 14 species belonging to the Corynoneura group (Diptera: Chironomidae: Orthocladiinae), from the Atlantic Forest, Brazil. Molecular analysis of cytochrome c-oxidase subunit I (COI) gene sequences supported 14 cohesive species groups, of which two similar groups were subsequently associated with morphological variation at the pupal stage. Eleven species previously described based on morphological criteria were linked to DNA markers. Furthermore, there is the possibility that there may be cryptic species within the Corynoneura group, since one group of species presented internal grouping, although no morphological divergence was observed. Our results support DNA-barcoding as an excellent tool for species delimitation in groups where taxonomy by means of morphology is difficult or even impossible.

Natural enemies that respond to prey in a density-dependent manner may be able to quickly suppress pest populations before they reach economically damaging levels. Although it is primarily the combination of a natural enemy's functional response and a population numerical response that will influence the maximum number of pests attacked, other factors may influence a density-dependent response. We conducted large-scale field experiments, both artificially inoculating grapevines with larvae and using naturally occurring populations, to quantify and characterize the response of a parasitoid, Dolichogenidea tasmanica (Cameron) (Hymenoptera: Braconidae) to different densities of its host, the pest of grapevines, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae). We showed that the response of D. tasmanica to the density of E. postvittana was inversely density-dependent, and that the degree of parasitism was consistently and significantly higher in the grape variety Cabernet Sauvignon compared with Chardonnay. While the significant effect of variety on the degree of parasitism may provide an option for increasing the parasitism of E. postvittana by D. tasmanica, it also highlights how differences in host plant can influence trophic interactions.

Plutella xylostella (L.) is the most important pest of Brassicaceae worldwide, with a recent estimate of US$ 4–5 billion expenditure for the control of this insect. A case of very high resistance of this pest to chlorantraniliprole was recently associated with reduced efficacy in a Brazilian field of Brassica spp. Although diamide resistance has been characterized, the fitness of insects due to such resistance has yet to be examined. Therefore, in this study, biological parameters were assessed in both susceptible and resistant strains of P. xylostella subjected to sublethal chlorantraniliprole concentrations. The field strain showed high resistance to chlorantraniliprole (RR50=27,793-fold), although resistance rapidly decreased in the first generations, showing instability. The exposure of susceptible and resistant larvae to their respective LC1, LC10, and LC25 values led to an increased duration of the larval and pupae phases and reduced weight in both strains; however, no significant differences in pupal viability across the treatments were observed. The resistant insects presented significantly lower larval weight and fecundity and higher larval and pupal periods, hatchability, and male longevity when not exposed to chlorantraniliprole, suggesting a fitness cost associated with resistance. In addition, resistant females showed a significantly higher egg-laying period and longevity at LC25, whereas the males lived longer at LC1. Chlorantraniliprole negatively impacted the biological parameters of both strains tested, although these effects were more relevant to the resistant insects. Resistant P. xylostella showed negative and positive biological trade-offs when compared with the susceptible individuals in both the absence and presence of chlorantraniliprole. Despite the important role that these trade-offs may play in the evolution of resistance to chlorantraniliprole, practical applications still depend on such information as the dominance of fitness costs and resistance.

The North American and European maize pest Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) was used to assess whether conditions of the natal field, subsequent laboratory rearing, or genetic population origin affect phenotypic traits of fitness, activity, or morphometrics. Standardized laboratory bioassays with large sample sizes revealed that none of the 16 tested traits, except crawling behaviours, appeared consistently stable across all seven tested colonies. Environmental conditions in the natal field of the F0 generation affected trait averages of the subsequently reared F1 generation in laboratory in ca. 47% of cases, and trait variability in 67% of cases. This was apparent for fitness and morphometrics, but less obvious for activity traits. Early generation laboratory rearing affected trait averages in ca. 56% of cases: morphometrics changed; fecundity and egg survival increased from F1 to F2. Trait variability increased or decreased in 38% of cases. Laboratory rearing for over more than 190 generations affected the trait averages in 60% of cases, reflected by decreases in flight activity and increases in body size, weight, and fecundity to some extent. It had little effect on trait variability, especially so for morphometric variability. The genetic population origin affected average levels of 55% and variability of 63% of phenotypic traits. A comparison among D. v. virgifera studies might be difficult if they use different populations or laboratory colonies. It is advised to consider possible effects of original field conditions, laboratory rearing, and population genetics when planning comparative studies targeting fitness, activity, or morphometric questions regarding Diabrotica species.