Colony kin structure and male production in Dolichovespula wasps

In annual hymenopteran societies headed by a single outbred queen, paternity (determined by queen mating frequency and sperm use) is the sole variable affecting colony kin structure and is therefore a key predictor of colony reproductive characteristics. Here we investigate paternity and male production in five species of Dolichovespula wasps. Twenty workers from each of 10 colonies of each of five species, 1000 workers in total, were analysed at three DNA microsatellite loci to estimate paternity. To examine the relationship between kin structure and reproductive behaviour, worker ovary activation was assessed by dissection and the maternal origin of adult males was assessed by DNA microsatellites. Effective paternity was low in all species (D. media 1.08, D. maculata 1.0, D. sylvestris 1.15, D. norwegica 1.08 and D. saxonica 1.35), leading to the prediction of queen-worker conflict over male production. In support of this, workers with full-size eggs in their ovaries (four out of five species) and adult males that were workers' sons (all five species) were found in queenright colonies. However, workers were only responsible for a minority of male production (D. media 7.4%, D. maculata 20.9%, D. sylvestris 9.8%, D. norwegica 2.6% and D. saxonica 34.6%) suggesting that the queen maintains considerable reproductive power over the workers. Kin structure and reproductive conflict in Dolichovespula contrast with their sister group Vespula. Dolichovespula is characterized by low paternity, worker reproduction, and queen-worker conflict and Vespula by high paternity, effective worker policing and absence of worker reproduction. The trend revealed by this comparison is as predicted by kin selection theory suggesting that colony kin structure has been pivotal in the evolution of the yellowjacket wasps.     

Taxonomy, distribution and nesting biology of species of the genus Dolichovespula (Hymenoptera, Vespidae)

The genus Dolichovespula consists provisionally of 18 species. Aerial nest site characteristics have been established for seven species but most of these species show flexibility in their choice of nest sites and two species often nest in shallow subterranean situations. Colony length is usually just over 3 months to approximately 4 months, but at lower latitudes may extend to more than 5 months. Mature colony size is usually approximately 1000 cells with more large cells than small cells. Parasitized colonies have a shorter colony cycle and smaller colonies. During the production of the sexual brood the larva/worker ratio reaches its lowest value of approximately 2.5 larvae per worker. Colonies often have upper mixed combs of small and large cells. Total adult production is usually less than 2000 adults. Colonies of D. arenaria and D. norwegica may specialize in mainly producing males or queens. Variations in mature colony size and production of queens is probably a consequence of the number of workers present, particularly early in the colony cycle.     

Climate change-driven body size shrinking in a social wasp

1. Climate change is expected to produce shifts in species distributions as well as behavioural, life-history, and/or morphological adaptations to find suitable conditions or cope with the altered environment. Most of our knowledge on this issue comes from studies on vertebrates, mainly endotherm species. However, it remains uncertain how small ectotherms, such as insects, respond to increased temperature. 2. This study tested whether climate change over the last 100 years (1904–2013) has affected morphological and functional traits in workers of the social wasp Dolichovespula sylvestris in the Iberian Peninsula. 3. Head width and forewing length, as well as body mass and wing area (assuming no change in shape), decreased over time and with increased mean annual temperature, even when controlling for geographical location and altitude. Interestingly, wing size decreased with a steeper slope compared with body size. If there is no change in wing shape, this would lead to an invariable wing loading (body mass:wing area ratio) over time, with potential consequences on flying ability of more recent (and thus smaller) wasp individuals. 4. These results suggest that recent climate change is leaving morphological signatures in social wasps, increasing the evidence for this phenomenon in insects. The data furthermore suggest that the known efficient thermoregulatory ability of social insect colonies may not successfully buffer the effect of global warming.     

Determination of some structural features of the nest paper materials of Dolichovespula Saxonica Fabricius, 1793 (Hymenoptera: Vespinae) in Turkey

The purpose of this paper is to identify the nest materials, some physical characteristics and the elemental composition of the nest of Dolichovespula saxonica (Fabricius, 1793). The nest surfaces were observed with a stereomicroscope and scanning electron microscope (SEM). In the inner surface of the D. saxonica nest the medium thickness of the fibers in the envelope and comb varied between 7.14 and 26.9 μm, respectively and averaged 16.4 μm. In the outer surface of the nest the medium thickness of the fibers in the envelope and comb were between 3.52 and 5.70 μm, respectively and averaged 4.63 μm. The nitrogen concentration of the nest of D. saxonica was 0.616% and the amount of protein was 3.08%. The percentages of the fibers, saliva, oil and the water absorption capacity were calculated as 67–70%, 23–30%, 12–18% and 110–140%, respectively. However, the amount of the element Cadmium (Cd) in the nest was found to have a value of 0.2 ppm. The major compounds of wasp nests are plant fibers, saliva and oil. However, the concentrations and ratios of the nest material compounds depend on the plant variety, place of origin, and time of harvest as well as on the processing and saliva conditions. The colors of the nest are beige, cream and grey with long dark brown lines. As a result of our study, we have found that the rates and quantities of physical characteristics, elemental composition and the fibers in the envelope and comb of the nest of D. saxonica change with environmental conditions.     

Colony stage and not facultative policing explains pattern of worker reproduction in the Saxon wasp

Inclusive fitness theory predicts that in colonies of social Hymenoptera headed by a multiple‐mated queen, workers should benefit from policing eggs laid by other workers. Foster & Ratnieks provided evidence that in the vespine wasp Dolichovespula saxonica, workers police other workers’ eggs only in colonies headed by a multiple‐mated queen, but not in those headed by a single‐mated one. This conclusion, however, was based on a relatively small sample size, and the original study did not control for possible confounding variables such as the seasonal colony progression of the nests. Our aim, therefore, was to reinvestigate whether or not facultative worker policing occurs in D. saxonica. Remarkably, our data show that in the studied Danish population, there was no correlation between worker–worker relatedness and the percentage of worker‐derived males. In addition, we show that variability in cuticular hydrocarbon profiles among the workers did not significantly correlate with relatedness and that workers therefore probably did not have sufficient information on queen mating frequency from the workers’ cuticular hydrocarbon profiles. Hence, there was no evidence that workers facultatively policed other workers’ eggs in response to queen mating frequency. Nevertheless, our data do show that the seasonal progression of the nest and the location in which the males were reared both explain the patterns of worker reproduction found. Overall, our results suggest that the earlier evidence for facultative worker policing in D. saxonica may have been caused by accidental correlations with certain confounding variables, or, alternatively, that there are large interpopulation differences in the expression of worker policing.     

Mating frequency, within-colony relatedness and male production in a yellow jacket wasp, Dolichovespula arenaria

We examined the mating frequencies of queens in a social wasp, Dolichovespula arenaria (Vespinae) using DNA microsatellites. Five of the seven colonies supported the hypothesis of single mating by queens. The other two colonies supported two and three matings, with effective paternity of 1.48 and 1.91. Mean worker relatedness was 0.77 +/- 0.09. In two of the four male-containing colonies, all were likely progeny of the queen. In the other two colonies workers produced 8 and 14% of the male wasps. Overall, 94.3% of the male wasps were likely progeny of the queen. These patterns are consistent with published studies of vespine wasps.     

Social wasps of the subfamily Vespinae (Hymenoptera, Vespidae) of the Kyrghyz Republic

Based on newly collected and museum material, the distribution of species of the Vespinae in the Kyrghyz Republic is discussed. Vespula austriaca is recorded for the first time from Kyrghyzstan. Dolichovespula norwegica is first reported in the Pamir‐Alai Mountains, providing the southernmost record for the species.     

Microsatellite loci for genetic research in the hornet Vespa mandarinia and related species

We developed 5 microsatelitte loci in the hornet Vespa mandarinia from RAPD fragments. The 5 loci showed 3–7 alleles in V. mandarinia and many were also polymorphic in the related species, V. ducalis, V. analis, Dolichovespula norvegicoides and Vespula schrenckii. These results suggested the loci will be useful for analyzing genetic structure of Vespinae, at both the colony and population levels.     

The structure of temperate yellowjacket communities is affected by land development and loss of forest cover

1. As anthropogenic disturbance continues to encroach on natural areas, it is imperative to establish how this disturbance affects species assemblages. Yellowjackets are important predators of a wide range of arthropods, acting as natural population control in many ecosystems. This study seeks to explore how Vespinae community structure shifts with increasing land development in a temperate North American environment.
2. Yellowjackets were sampled from May to September 2019 using heptyl butyrate and acetic acid plus isobutanol traps. Sampling sites represented a gradient of developed landscapes, from fully forested to entirely developed. Seven species from the genera Dolichovespula and Vespula were trapped during the study.
3. Yellowjacket community structure was found to be significantly affected by the amount of land development. These results were driven by the replacement of Vespula consobrina with Vespula germanica in urban landscapes. A high level of development, greater than 75%, reduced species abundance relative to the fully forested landscapes, primarily due to the loss of Vespula pensylvanica and V. consobrina.
4. Our results highlight that the replacement of forested areas with urban development causes a shift in yellowjacket community composition, favouring generalist scavengers (e.g. V. germanica) and threatening the abundance of forest specialists such as V. consobrina.