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Invasive paper wasps such as Polistes dominula are a major pest and problem for biodiversity around the globe. Safe and highly targeted methods for the control of these and other social wasp populations are needed. We attempted to identify potentially-lethal gene targets that could be used on adult paper wasps in a gene silencing or RNA interference (RNAi) approach. Double-stranded RNA (dsRNA) was designed to target genes for which silencing has proven lethal in other insects. dsRNA was provided either orally to foragers or directly injected into the wasps. We also provided the dsRNA unprotected or protected from degradation by gut nucleases in two different forms (lipofectamine and carbon quantum dots). The effects of oral delivery of 22 different gene targets to forager wasps was evaluated. The expression of five different genes was successfully reduced following dsRNA ingestion or injection. These gene targets included the FACT complex subunit spt16 (DRE4) and RNA-binding protein fusilli (FUSILLI), both of which have been previously shown to have potential as lethal targets for pest control in other insects. However, we found no evidence of significant increases in adult wasp mortality following ingestion or injection of dsRNA for these genes when compared with control treatments in our experiments. The methods we used to protect the dsRNA from digestive degradation altered gene expression but similarly did not influence wasp mortality. Our results indicate that while many of the same gene targets can be silenced and induce mortality in other insects, dsRNA and RNAi approaches may not be useful for paper wasp control.

Monarch butterflies can be infected by a parasite called OE. Butterflies with OE may not complete their development or, if they do, the adult butterflies might have deformed wings. We found that the proportion of adult butterflies with wing deformities increased further south in New Zealand, where the weather is colder. In contrast, the number of butterflies infected with the OE parasite decreased further to the south. No OE was observed in butterflies from the coldest, southernmost location of Dunedin, while all butterfly samples from the warmest, northernmost site at the top of the North Island were infected. The OE parasite seems to vary on a north-south gradient, with more OE in the north and less in the south. Our analysis showed that being parasitised by OE did not mean butterflies were more likely to have wing deformities. We think that the colder temperatures in the south of the country limit the development of the OE parasite and independently cause the wing deformities seen in the adult butterflies.

Wasps of the genus Vespula are social insects that have become major pests and predators in their introduced range. Viruses present in these wasps have been studied in the context of spillover from honey bees, yet we lack an understanding of the endogenous virome of wasps as potential reservoirs of novel emerging infectious diseases. We describe the characterization of 68 novel and nine previously identified virus sequences found in transcriptomes of Vespula vulgaris in colonies sampled from their native range (Belgium) and an invasive range (New Zealand). Many viruses present in the samples were from the Picorna-like virus family (38%). We identified one Luteo-like virus, Vespula vulgaris Luteo-like virus 1, present in the three life stages examined in all colonies from both locations, suggesting this virus is a highly prevalent and persistent infection in wasp colonies. Additionally, we identified a novel Iflavirus with similarity to a recently identified Moku virus, a known wasp and honey bee pathogen. Experimental infection of honey bees with this novel Vespula vulgaris Moku-like virus resulted in an active infection. The high viral diversity present in these invasive wasps is a likely indication that their polyphagous diet is a rich source of viral infections.

1. Host���parasite interactions represent complex relationships among species, often with considerable spatial variation. We examined latitudinal variation in the prevalence of monarch butterfly (Danaus plexippus) infection by the protozoan parasite Ophryocystis elektroscirrha via a citizen science project in New Zealand. Parasitism by O. elektroscirrha can result in incomplete development causing mortality, or adult butterflies with deformed wings and reduced fitness. 2. We established the existence of counter-latitudinal clines of wing deformities and parasite prevalence in monarchs, which in New Zealand are non-migratory. The prevalence of wing deformities increased with increasing latitude, whereas the prevalence of parasite infections decreased with increasing latitude. No parasitism was observed in our highest latitudinal location, while all butterfly samples were infected in the warmest and lowest latitudinal site. The prevalence of parasitism or wing deformity did not vary with the butterfly sex. 3. Cold temperatures appear to independently affect the parasite and host butterfly development, with lower temperatures limiting parasite development and inducing wing deformities in butterflies. Other protozoan parasites display similar latitudinal clines that are thought to be temperature related. 4. Environmental factors appear to independently influence insect populations through different mechanistic pathways. The high prevalence of parasite infections may affect butterfly fitness in warmer regions, but the cooler conditions at higher latitudes manifest as a major fitness cost, deformed wings. Monarch butterflies in New Zealand and around the world may perform better where it is not too hot (and optimal for these parasites), but not cold (where the pupae experience developmental issues).

The German wasp (Vespula germanica) is a highly successful invader on a global scale. These wasps were first observed in the Western Cape region in South Africa in 1972, and they have the potential to expand their range and cause significant damage to the native biodiversity. Our study used nuclear (DNA microsatellites) and mitochondrial DNA (mtDNA) from 42 wasp colonies to analyse the population genetics of V. germanica in their invaded South African range. We sequenced three mitochondrial genes; cytochrome c oxidase I, cytochrome b and cytochrome c oxidase II. We found six mtDNA haplotypes present in South Africa. Although only a single fertilized queen is sufficient for the establishment of a wasp nest, the probability of a single introduced queen to successfully establish a nest and a population is very small. If multiple queens were introduced at the same time, the probability for more than one haplotype being transferred to the new population increases. Therefore, the true number of queen introductions occurred in South Africa can be inferred to be between two and six. We examined nine microsatellite loci and found weak-to-no genetic sub-structuring, likely due to high dispersal rates. We concluded that German wasps in South Africa maintain a homogenous population with movement of individuals between localities.

Premise of the study: Microsatellite markers were developed for Arthropodium cirratum (Asparagaceae) to study population genetic structure and translocation of this species. These markers were tested for cross-amplification in two other Arthropodium species. Methods and Results: Sixteen microsatellite markers were developed from a genomic library and tested in three populations of A. cirratum. The loci exhibited one to five alleles per locus, with private alleles present in each of the populations. Cross-amplification tests in the two other New Zealand Arthropodium species revealed that many of the loci amplify and demonstrate polymorphism in A. bifurcatum. Conclusions: These markers will be useful for determining genetic structure in A. cirratum and for determining the origins of translocated populations of this species.