A citizen science project reveals contrasting latitudinal gradients of wing deformity and parasite infection of monarch butterflies in New Zealand

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)

Wing Deformities in Monarch Butterflies in New Zealand: The Role of a Parasite and the Climate

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

Population genetics of the invasive wasp Vespula germanica in South Africa

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

Genomic analyses of fairy and fulmar prions (Procellariidae: Pachyptila spp.) reveals parallel evolution of bill morphology, and multiple species

Prions are small petrels that are abundant around the Southern Ocean. Here we use mitochondrial DNA (COI and cytochrome b) and nuclear reduced representation sequencing (ddRADseq) to examine the relationships within and between fairy (Pachyptila turtur) and fulmar (P. crassirostris) prions from across their distributions. We found that neither species was recovered as monophyletic, and that at least three species were represented. Furthermore, we detected several genetic lineages that are also morphologically distinct occurring in near sympatry at two locations (Snares Islands and Chatham Islands). The factors that have driven diversification in the fairy/fulmar prion complex are unclear but may include philopatry, differences in foraging distribution during breeding, differences in non-breeding distributions and breeding habitat characteristics. The observed distribution of genetic variation in the fairy/fulmar prion complex is consistent with population expansion from ice-free Last Glacial Maximum refugia into previously glaciated areas

Gene silencing for invasive paper wasp management: Synthesized dsRNA can modify gene expression but did not affect mortality

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

Use of artificial nest boxes by two species of small, arboreal mammals in Ecuadorian tropical dry forest

We record, for the first time, the nest structure of two species of small, non-volant mammals, Marmosa simonsi and Rhipidomys latinamus, inside artificial nest boxes in a dry forest ecosystem of Western Ecuador. We describe the nests and categorized them as rearing nest, permanent resting nest and transient refuge, depending on their intended use. Artificial nest boxes provide an optimal place for pup rearing and resting for small mammals, and they can be useful for ecological studies of elusive, poorly-known mammalian species

Viruses and their effects in ants (Hymenoptera: Formicidae)

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The potential for a CRISPR gene drive to eradicate or suppress globally invasive social wasps

CRISPR gene drives have potential for widespread and cost-efficient pest control, but are highly controversial. We examined a potential gene drive targeting spermatogenesis to control the invasive common wasp (Vespula vulgaris) in New Zealand. Vespula wasps are haplodiploid. Their life cycle makes gene drive production challenging, as nests are initiated by single fertilized queens in spring followed by several cohorts of sterile female workers and the production of reproductives in autumn. We show that different spermatogenesis genes have different levels of variation between introduced and native ranges, enabling a potential ‘precision drive’ that could target the reduced genetic diversity and genotypes within the invaded range. In vitro testing showed guide-RNA target specificity and efficacy that was dependent on the gene target within Vespula, but no cross-reactivity in other Hymenoptera. Mathematical modelling incorporating the genetic and life history traits of Vespula wasps identified characteristics for a male sterility drive to achieve population control. There was a trade-off between drive infiltration and impact: a drive causing complete male sterility would not spread, while partial sterility could be effective in limiting population size if the homing rate is high. Our results indicate that gene drives may offer viable suppression for wasps and other haplodiploid pests

Polistes versicolor (Hymenoptera: Vespidae), an Introduced Wasp in the Galapagos Islands: Its Life Cycle and Ecological Impact

The yellow paper wasp, Polistes versicolor (Olivier) was first recorded in the Galapagos archipelago in 1988. Its life cycle and ecological impacts were studied on two islands 11 yr after it was first discovered. This invasive wasp adapted quickly and was found in most environments. Colony counts and adult wasp monitoring showed a strong preference for drier habitats. Nest activities were seasonally synchronized, nest building followed the rains in the hot season (typically January-May), when insect prey increases, and peaked as temperature and rains started to decline. Next, the number of adult wasps peaked during the cool season when there is barely any rain in the drier zones. In Galapagos, almost half of the prey loads of P. versicolor were lepidopteran larvae, but wasps also carried spiders, beetles, and flies back to the colonies. An estimated average of 329 mg of fresh insect prey was consumed per day for an average colony of 120-150 wasp larvae. The wasps preyed upon native and introduced insects, but likely also affect insectivorous vertebrates as competitors for food. Wasps may also compete with native pollinators as they regularly visited flowers to collect nectar, and have been recorded visiting at least 93 plant species in Galapagos, including 66 endemic and native plants. Colonies were attacked by a predatory moth, Taygete sphecophila (Meyrick) (Lepidoptera: Autostichidae), but colony development was not arrested. High wasp numbers also affect the activities of residents and tourists. A management program for this invasive species in the archipelago is essential

A diverse viral community from predatory wasps in their native and invaded range, with a new virus infectious to honey bees

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