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Temperature plays an important role in winter diapause of temperate insects. Its effects can cause problems for biological control programs, both for the establishment of insects in novel climates and for the mass rearing of insects in the laboratory. Hypena opulenta (Christoph) (Lepidoptera: Erebidae), a biological control agent for invasive swallow‐wort species in North America, has been observed to enter diapause in mid‐summer in its introduced range. Additionally, H. opulenta has proved complicated to mass‐rear, in part because individuals sometimes enter diapause unexpectedly, meaning that diapausing pupae may need to be stored over winter for varying lengths of time. We conducted pupal storage experiments to determine the effects of high pre‐winter temperatures, like those experienced by early diapausing individuals in the field, on lipid store depletion. We conducted a second experiment to compare the effects of cold treatments of different lengths (1, 3, and 6 months), during diapause, on pupal mortality, development times, and the synchrony of adult emergence. Exposure to warm periods ranging from 25 to 75 days during early diapause did not affect pupal weight, adult emergence rates, or lipid store depletion in H. opulenta. Conversely, the length of cold exposure (between 1 and 6 months) during diapause clearly affected moth mortality, and the timing and consistency of adult emergence. Longer cold periods (3 and 6 months) resulted in earlier, more synchronous adult emergence, and lower diapause mortality, than shorter cold periods (1 month). Our results indicate that in terms of energy depletion, early diapause will not affect the fitness of emerging adults, which is important for the viability of univoltine populations in the southernmost part of the introduced range. Additionally, our results will assist with the H. opulenta mass rearing program, indicating the timing required to synchronize adult emergence. [ABSTRACT FROM AUTHOR]

The 6/04 standard of the European and Mediterranean Plant Protection Organisation (EPPO) on the safe use of biological control is a decision-support scheme (DSS) for the import and release of biological control agents in Europe. It was recently developed by the Joint EPPO/International Organisation of Biological Control (IOBC) Panel on Biological Control Agents. The DSS can be used to assess the potential environmental impacts of biological control agents. It is valid for different types of biological control: classical and augmentative biological control of invertebrates, pathogens and weeds. However, the DSS is not yet widely implemented in Europe and, during preliminary trials, it was found that its broad range of usages could lead to some confusion or misunderstandings, as well as requiring unnecessary information in some cases. Thus, the scheme was modified to specifically assess classical biological control against plant pests, i.e. the introduction of exotic natural enemies of plant pests for establishment and long-term control. The new version of the scheme was then tested on two parasitoids that are presently being released in Europe, the figitid Ganaspis cf. brasiliensis against the spotted wing drosophila Drosophila suzukii and the mymarid Cleruchoides noackae against the Eucalyptus bronze bug Thaumastocoris peregrinus. Both parasitoids were successfully assessed with the new version of the DSS. No major issues were encountered during the assessments and most questions were answered with low levels of uncertainty. Both assessments concluded that the parasitoids were safe to release in the impact assessment areas, with positive impacts exceeding negative impacts. Suggestions for potential improvements are provided. [ABSTRACT FROM AUTHOR]

The seasonal pattern of parasitism by a parasitoid can be influenced by many factors, such as interspecific competition and host instar preference. We conducted field and laboratory experiments to describe the seasonal pattern of parasitism of spruce budworm Choristoneura fumiferana (Clemens) larvae by Tranosema rostrale (Brischke), and to investigate whether this pattern can be explained by interaction with other parasitoid species, or by host instar preference. Larval survival, developmental time, sex ratio, and adult size of T. rostrale developing in different host instars were also measured to further assess the potential importance of host instar on parasitoid life history. Parasitism by T. rostrale increased over the season, reaching the highest rate during the fourth-instar larva, and then decreased again until the sixth-instar. At the same time, parasitism by another parasitoid, Elachertus cacoeciae (Howard), increased over the season, and multiparasitism with T. rostrale suggests potential competition between these two parasitoids. Tranosema rostrale showed no host instar preference when third- to sixth-instar larvae were exposed simultaneously in a manipulative field experiment. The proportion of females emerging from spruce budworm larvae increased over the season; however, no difference in sex ratio was observed in the manipulative field experiment. Only male pupal development time and adult size were marginally increased in fifth-instar spruce budworm larvae. We conclude that T. rostrale's seasonal phenology or competition with E. cacoeciae, but not host instar preference, were possibly responsible for the observed seasonal pattern of parasitism. [ABSTRACT FROM AUTHOR]

During the last decade, the spotted wing drosophila, Drosophila suzukii, has spread from eastern Asia to the Americas, Europe, and Africa. This fly attacks many species of cultivated and wild fruits with soft, thin skins, where its serrated ovipositor allows it to lay eggs in undamaged fruit. Parasitoids from the native range of D. suzukii may provide sustainable management of this polyphagous pest. Among these parasitoids, host-specificity testing has revealed a lineage of Ganaspis near brasiliensis, referred to in this paper as G1, that appears to be a cryptic species more host-specific to D. suzukii than other parasitoids. Differentiation among cryptic species is critical for introduction and subsequent evaluation of their impact on D. suzukii. Here, we present results on divergence in genomic sequences and architecture and reproductive isolation between lineages of Ganaspis near brasiliensis that appear to be cryptic species. We studied five populations, two from China, two from Japan, and one from Canada, identified as the G1 vs G3 lineages based on differences in cytochrome oxidase l sequences. We assembled and annotated the genomes of these populations and analyzed divergences in sequence and genome architecture between them. We also report results from crosses to test reproductive compatibility between the G3 lineage from China and the G1 lineage from Japan. The combined results on sequence divergence, differences in genome architectures, ortholog divergence, reproductive incompatibility, differences in host ranges and microhabitat preferences, and differences in morphology show that these lineages are different species. Thus, the decision to evaluate the lineages separately and only import and introduce the more host-specific lineage to North America and Europe was appropriate., Competing Interests: Conflicts of interest The author(s) declare no conflicts of interest., (Published by Oxford University Press on behalf of The Genetics Society of America 2024.)