Including Host Availability and Climate Change Impacts on the Global Risk Area of Carpomya pardalina (Diptera: Tephritidae)

Fruit flies are a well-known invasive species, and climate-based risk modeling is used to inform risk analysis of these pests. However, such research tends to focus on already well-known invasive species. This paper illustrates that appropriate risk modeling can also provide valuable insights for flies which are not yet “on the radar.” Carpomya pardalina is a locally important cucurbit-infesting fruit fly of western and central Asia, but it may present a risk to other temperate countries where melons are grown. MaxEnt models were used to map the risk area for this species under historical and future climate conditions averaged from three global climate models under two shared socio-economic pathways in 2030 and 2070 from higher climate sensitivity models based on the upcoming 2021 IPCC sixth assessment report. The results showed that a total of 47.64% of the world’s land mass is climatically suitable for the fly; it could establish widely around the globe both under current and future climates with host availability. Our MaxEnt modeling highlights particularly that Western China, Russia, and other European countries should pay attention to this currently lesser-known melon fly and the melons exported from the present countries. The current and expanding melon trade could offer direct invasion pathways to those regions. While this study offers specific risk information on C. pardalina, it also illustrates the value of applying climate-based distribution modeling to species with limited geographic distributions.

Ovigeny strategy of the parasitic wasp Cosmocomoidea annulicornis (Hymenoptera: Mymaridae): effect of female age, feeding and host availability on reproductive traits

The reproductive traits of the mymarid wasp Cosmocomoidea annulicornis (Ogloblin) (Hymenoptera: Mymaridae) attacking eggs of the sharpshooter Tapajosa rubromarginata (Signoret) (Hemiptera: Cicadellidae) were evaluated under laboratory conditions. Bioassays were carried out to estimate the realized fecundity and egg load of females. The ovigeny index was calculated and different biological traits, such as body size, oöcyte length, gaster length and wing length, were analysed to assess significant associations between these traits and the species fitness. In addition, the effect of host availability and feeding on longevity and potential fecundity throughout life and the effect of female age on egg maturation dynamics were assessed. The results showed that C. annulicornis is a strongly synovigenic species. A positive correlation was found between fecundity and longevity of the females and between body size and oöcyte length. Contrary to expected, body size was not related to fecundity and longevity. Females lived significantly longer in the presence of hosts and honey than when they were host-deprived and honey-fed or both host and honey deprived. Host availability had a significant effect on the amount of eggs laid by C. annulicornis females. Female age was negatively associated with oöcyte length. Furthermore, females were able to mature additional eggs as they aged, nevertheless, when host-deprived, senescent females presented significantly less mature eggs than younger ones, suggesting a possible egg oosorption. These results might contribute to a better understanding of the reproductive potential of this species as a biocontrol agent.

Influence of rice crop stage on the distribution of hymenopteran parasitoids of insect pests

A total of 43 insect parasitoid species belonging to fourteen families (Aphelinidae, Braconidae, Ceraphronidae, Diapriidae, Encyrtidae, Eulophidae, Eurytomidae, Ichneumonidae, Megaspilidae, Mymaridae, Platygasteridae, Proctotrupidae, Pteromalidae, Trichogrammatidae) has been documented in the rice ecosystem using yellow pan trap. The observations were made at four important stages of rice crop like early tillering, active tillering, booting and panicle development. The parasitoids were also compared with the occurrence of sixteen insect pests that were recorded simultaneously in each stage of the crop. The result revealed that, there is a significant difference in the occurrence of parasitoids according to the stage of the crop and insect host availability. This understanding help in the introduction of specific parasitoids at respective stages for effective biocontrol.

The effects of host availability and fitness on Aedes albopictus blood feeding patterns in New York

Aedes albopictus is a competent vector of numerous pathogens, representing a range of transmission cycles involving unique hosts. Despite the important status of this vector, variation in its feeding patterns is poorly understood. We examined the feeding patterns of Ae. albopictus utilizing resting collections in Long Island, New York, and contextualized blood meal sources with host availability measured by household interviews and camera traps. We identified 90 blood meals, including 29 human, 22 cat, 16 horse, 12 opossum, 5 dog, 2 goat, and 1 rabbit, rat, squirrel and raccoon. Our study is the first to quantitatively assess Ae. albopictus feeding patterns in the context of host availability of wild animals in addition to humans and domestic animals. Host feeding indices showed that cats and dogs were fed upon disproportionately often compared to humans. Forage ratios suggested a tendency to feed on cats and opossums and to avoid raccoons, squirrels, and birds. This feeding pattern was different from another published study from Baltimore, where Ae. albopictus fed more often on rats than humans. To understand if these differences were due to host availability or mosquito population variation, we compared the fitness of Long Island and Baltimore Ae. albopictus after feeding on rat and human blood. In addition, we examined fitness within the Long Island population after feeding on human, rat, cat, horse, and opossum blood. Together, our results do not show major mosquito fitness differences by blood hosts, suggesting that fitness benefits do not drive Northeastern Ae. albopictus feeding patterns.

Overwintering mortality of the oak lace bug (Corythucha arcuata) in Hungary – a field survey

The North American oak lace bug (Corythucha arcuata) was first discovered in Europe (Norhern Italy) in 2000. It started a rapid area expansion in the last decade and has been reported in 20 countries so far. Almost all European oaks are suitable hosts. On top of the host availability, abiotic factors like weather/climate may also have a decisive impact on its further spread and future outbreaks. We conducted a simple field survey within three years, at five locations to estimate the overwintering mortality of the species. Our results suggest that not even a relatively harsh winter (as 2016/2017) caused severe mortality in the overwintering populations. The average mortality of the nine year/location combinations was 30.6% (range 9.1–58.5%). Based on this, the low winter temperature is unlikely to restrict its further spread, therefore continuing area expansion can be predicted.

Host Availability, Repulsive Companion Planting, and Predation Interact and Shape How a Parthenogenetic Aphid Population Responds to a Stratified Ecological Challenge

Phloem-feeding insects strive to offset the disadvantageous effects of stressors to sustain their offspring and survive. Adaptive responses to environmental stress are not well understood under complex influences of companion planting, natural enemies, and host gradient. In this study, under predation by lacewing Chrysoperla carnea Stephens (Neuroptera: Chrysopidae), we survey the responses of green peach aphid Myzus persicae Sulzer (Hemiptera: Aphididae), reared on different densities of cabbage Brassica oleracea L. (Brassicales: Brassicaceae) to its shallot companion Allium cepa (L.) var. aggregatum G. Don (Asparagales: Amaryllidaceae). Firstly, aphid aggregative abundance was strongly influenced by shallot perturbation, predator presence and changes in cabbage-host biomass, altering aphid phenotypic plasticity. Interestingly, the shallot and predation negative impacts can be of similar magnitudes. Secondly, changes in the cabbage-host availability and biomass, especially under predation, had a strong impact on aphid traits. Our study underscores the benefits of including shallots as crop-companions in augmenting pest control, but also suggests that the outcome of coupling companion planting with natural enemies is context-dependent and thus should be empirically applied. At the confluence of ecology and agronomy, this work provides insights on how manipulated functional biodiversity may function as an alternative strategy for pestilent herbivory management in model and green-house systems.