Local dynamics of worker activity of the invasive Vespula germanica and V. vulgaris (Hymenoptera: Vespidae) wasps in Argentina

Abstract

1. The abundance of insects depends essentially on the reproductive success of individuals. In social insects, however, the abundance of sterile workers outside a nest depends on colony size but is also determined by ontogeny, nest demands, and local environmental factors. For invasive social wasps, the drivers of worker abundance are important because they determine the impact that these species have on the native systems, people, and their goods. 2. The aim of the present study was to understand the relative importance of endogenous and exogenous factors on the abundance of workers of populations of Vespula spp., by analysing 12 years of trap captures in NW Patagonia. This is the first attempt to model the activity levels of invasive Vespula spp. wasps over time in Argentina. 3. It was shown that between years, the worker activity of both vespids presents fluctuations, and that of V. germanica is determined by the spring mean temperatures. Within the flight season, V. germanica worker activity is affected by the relative abundance of workers in that year, whereas for V. vulgaris, activity it is affected by the relative abundance of both species that year. We found no relationship between individual weather variables and activity within a flight season for both wasps. 4. The patterns observed for Argentina are similar to those observed in all invaded temperate areas where Vespula spp. are established. This study provides useful information to understand the driving factors that affect Vespula spp. worker activity in Argentina. This could be a necessary step to develop plans to manage these invasive social insects.

The long‐term population dynamics of common wasps in their native and invaded range

“…Beirne () found evidence for the effects of spring rainfall on wasp abundance in England. The most recent analyses of wasps in the invaded range have also highlighted the role of spring conditions on wasp abundance in New Zealand (Barlow, Beggs & Barron ) and Argentina (Masciocchi, Pereira & Corley ). These previous and our current analysis suggest that the incipient stage of the wasp colony formation is the most susceptible to environmental variation.…”

“…spring temperature and spring rainfall), which have been recognised as influencing results and conclusions in prior time-series analyses (e.g. Masciocchi, Pereira & Corley 2016). The different variables chosen in each country may also be reflective of the differences in environment between countries.…”

“…Common wasps typically overwinter alone as mated queens, with winter conditions representing a bottleneck through which only larger queens with higher fat reserves appear to survive (Harris & Beggs 1995). Colder and wetter conditions in this incipient spring phase of the wasp life cycle have been related to lower wasp abundances (e.g., Akre & Reed 1981;Barlow, Beggs & Barron 2002;Masciocchi, Pereira & Corley 2016). Other researchers, however, have failed to find any relationship between spring weather and variation in annual wasp abundances (Fox-Wilson 1946;Archer 1985).…”

Species Composition, Abundance and Seasonal Phenology of Social Wasps (Hymenoptera: Vespidae) in Wisconsin Vineyards

“…Fluctuating population dynamics have been documented for V. germanica and V. vulgaris [ 40 , 41 , 42 ], likely due to their pest status and propensity for invading new geographical regions [ 43 ], and this information is lacking for other species. As noted by Akre and Reed [ 44 ], different species exposed to similar weather conditions do not necessarily experience similar fluctuations in population dynamics, which suggests that endogenous biotic factors, such as relative population abundance, may vary by species [ 42 ]. More research is necessary to determine if long term population dynamics patterns described for V. germanica and V. vulgaris apply to other social wasps species, such as V. vidua .…”

Which temporal resolution to consider when investigating the impact of climatic data on population dynamics? The case of the lesser horseshoe bat (Rhinolophus hipposideros)

“…In a few cases, the number of variables were reduced by pre-selecting months based on preliminary analysis (Parent et al 2016) or on expert knowledge (Kerbiriou et al 2015). Most studies have aggregated climatic data to correspond to climatic seasons (varying from two to six month periods) that are consistent with the life cycle of the species of interest (Bruggeman et al 2015;Bleho et al 2015;Ciuti et al 2015;Kanno et al 2016;Dugger et al 2016;Masciocchi et al 2016;Townsend et al 2016). Occasionally, studies even considered these data by averaging them over a year (Nouvellet et al 2013).…”