Behavioural patterns and morphological advantages favour successful use of Crematogaster schmidti trails by Camponotus lateralis WORKERS (HYMENOPTERA: FORMICIDAE)

The paper examines the relationship between two ant species: Camponotus lateralis and Crematogaster schmidti in the neighboring habitat in the biocenoses of the Southern Coast of the Crimea (Ukraine). The ecological characteristics of the species are given, the structure of forage areas is described, as well as the daily activity of ants in shared habitats. It was shown that Camponotus lateralis accesses the food resources of Crematogaster schmidti using their trails. As a result of a frame-by-frame analysis of the video recordings, a number of behavioural responses have been identified for each species that it displays during interspecific contacts on the trails. It was shown that Camponotus lateralis successfully avoids contact by changing its trajectory at a distance of about 1 cm from Crematogaster schmidti workers. The aggressive reaction of Crematogaster schmidti was only recorded in few cases after antenna contacts. In most cases, Camponotus lateralis reacted more quickly than Crematogaster schmidti after antennal contact and changed its trajectory. The structural characteristics of the antennae and eyes of workers of both species were compared. Camponotus lateralis workers were shown to have longer antennae on average. The eyes of Camponotus lateralis have, on average, more facets than those of Crematogaster schmidti and, on average, more facets per unit of eye area. The significance of these morphological advantages of Camponotus lateralis for the successful use of Crematogaster schmidti trails is discusse

Trail activity of ants (Hymenoptera, Formicidae) at different habitat structure

and in 2019-2021 at the city of Kyiv in the region of Carpathians, Ukraine and in the city of Tashkent in Uzbekistan. The study covered natural (forest, meadow, steppe), suburban (alleys and tree planting) and urban habitats (tree planting along streets and roads, botanical gardens). The average number of workers on the trails per 2 minutes (activity) are obtained for each of the 21 dominant species of ants. Urbanized habitats are favorable for some ant species (Crematogaster subdentata and Lasius neglectus - invasive or native species, depending on the region, Dolichoderus quadripunctatus - native species), it is reflected in the maximum rates of activity on the trails. In urbanized habitat there are about 200-800 individuals of ants that can be observed on the trails, it is equal to or greater than the activity for other ant species in natural habitats (100-400 individuals per 2 minutes). In the primary range (Uzbekistan), activity indicators on trails in native species C. subdentata and L. neglectus are equal or lower than those in the secondary range (Crimea, Kyiv city, Ukraine). The maximum activity of L. neglectus on trails in urbanized habitats is in Tashkent city, less in Crimea (M-W test, Tashkent vs Crimea, P≤0.001), and in Kyiv city (Tashkent vs Kyiv, P≤0.001). For C. subdentata, the maximum activity in the conditions of Tashkent, less activity - in natural habitats (tugai forests) (Tashkent vs tugai, P≤0.001). The presence of permanent foraging trails indicates the dominant status of the ant species. The amount of traffic on the trails can vary greatly in different habitats

Acquisition of invasive traits in ant, Crematogaster subdentata mayr (Hymenoptera: Formicidae) in urban environments

The native (primary) range of Crematogaster subdentata Mayr lies in Central Asia. Within the secondary range in Ukraine and Russia, it is invasive. The 1st objective of this work was to study the evolution of the biological and ecological features (habitats, queen number, colony structure, behavior, worker’s activity on foraging trails) of C. subdentata in the urban environments (Tashkent) and secondary ranges (Crimea, Rostov-On-Don region). Whilst, the 2nd objective was to compared these parameters in the natural habitats in the native (Uzbekistan) range. Result showed that in the territory of the primary range in Kyzylkum, colonies of C. subdentata are strictly monogynous; in Zarafshan’s oasis (riparian forests) they were polygynous (5.0±1.2 queens), but in cities of Uzbekistan C. subdentata forms supercolonies with hundreds of nests, and in total with hundreds of queens (on average 17.7±4.4 queens per one nest in supercolony). In the secondary range, C. subdentata forms even larger supercolonies with thousands of nests, containing 53.0±8.7 queens per nest. C. subdentata avoids contacts with another invasive ant species, Lasius neglectus, in the foraging territories both in the primary and secondary ranges, but other ant species avoid C. subdentata. Workers of C. subdentata are aggressive toward conspecific ones from other nests in the natural habitats, but are tolerance to those in both the secondary range and in the cities in the primary range. In conclusion, our results show that some ants may acquire invasive species traits in the urban habitats in the primary range

Nuptial flight in ants (Hymenoptera: Formicidae)

Based on the collected data set (758 observations for the period 2007-2021) on the dates of the nuptial flight for 73 species of ants, an analysis of possible time shifts due to global climate changes has been carried out. It was found that for Eastern Europe and Asia, for most species of ants, the dates of nuptial flight were shifted by at least two weeks earlier in comparison with the data for Western Europe. In a cold climate, there are significant changes, towards earlier dates, in the phenology of nuptial flight for two species: Lasius flavus (P<0.05) and Polyergus rufescens (P<0.01). The corresponding rates of change are 3.9 and 6.25 days per year. In other types of climate, no significant changes in the phenology of the nuptial flight were found. Taking into account the boundaries of future climatic zones in temperate and arid zones, such changes were recorded for several species. Solenopsis fugax in temperate climates shows a tendency to delay flight at a rate of 6 days per year (P<0.05). Within the predicted boundaries of the arid climate, the flight phenology delay was recorded for Lasius niger (5.8 days per year; P<0.01) and Messor sp. (4.4 days per year; P<0.05). At the same time, for Polyergus rufescens, there is a tendency to an earlier flight at a rate of eight days per year (P<0.05). No connection was found between the date of nuptial flight and the geographic distance between populations (or locations)