A further study of the nesting biology of Leptochilus (Neoleptochilus) regulus (de Saussure, 1855) (Hymenoptera, Vespidae, Eumeninae)

Two females of Leptochilus regulus (de Saussure, 1855) were observed nesting in reed stalks of a Fabre’s hive serving as a block of trap nests in Crimea, with the timekeeping of all their nesting behaviours. The building material used by the females to separate the nesting cavity into the cells consisted of pellets of dry soil, gravel particles, and small fragments of tree bark, leaves, and thin stems. Females rapidly carried these items collected in 1.0–1.5 m from the nests. They bonded only the last portions of the building material in each “partition” with a very small amount of mud. An additional amount of unbonded building material items was deposited into the nest after sealing the last nest cell. Females hunted exclusively for small larvae of an anobiid beetle (Coleoptera, Anobiidae); they stored 19–37 prey items per cell. Hunting and provisioning occupied the largest portion of the females’ time budget. Duration of hunting flights was different between the females. The nests of both females contained three brood cells. Cocoons of Chrysis ragusae De Stefani, 1888 (Hymenoptera, Chrysididae) were found in the nests; females of this cuckoo wasp species were also recorded entering the host nests at the stage of provisioning, acting apparently as inquilines. The cocoon ultrastructure of L. regulus is illustrated and discussed.

The nesting and mating behavior of Andrena patella (Hymenoptera: Andrenidae)

This study of nesting and associated behavior patterns of Andrena patella was carried out at 27 locations with different landscape categories, from 2013 to 2016. The research areas chosen were generally flat or marshy areas. A total of 15 major nest aggregations were spotted and 120 nests were excavated. This species nests in soil, males emerge earlier than females, and mating occurred on flowers during the foraging season, in the 3rd week of May. The various nest and cell parameters showed low variability in the different years and different sites, but nest cell length, diameter and number varied significantly, as well as depth even at the same site. The nests were multi-cellular, oblique to horizontal, and cell shape was oval. The mating attempts of the pairs and copulatory behavior involved various steps which were completed in a very few seconds. The males appeared first on the flowers, near to the nesting site, and lived shorter than the females. The females started foraging in the 2nd to 3rd weeks of May and laid eggs in the 1st week of June. The adult phenology, egg placement, cell provision and larval feeding are described.

A bilateral gynandromorph of Discoelius dufourii (Hymenoptera, Vespidae, Zethinae): morphology and mating behaviour

A gynandromorph is an organism combining both female- and male-type tissues. While the vast majority of studies have described the morphology of gynandromorphs, their sexual behaviours remain under-explored. We studied a predominantly bilateral gynandromorph specimen of the predatory wasp Discoelius dufourii (Hymenoptera: Vespidae: Zethinae) reared from a trap-nest. In addition to describing the morphology, we explored the gynandromorph’s response to a conspecific female, comparing it with the behavioural interactions between normal males and females of D. dufourii and the phylogenetically related D. zonalis. For most specific behavioural elements, males of both Discoelius species exhibited a greater frequency and a higher probability of occurrences of the behaviour than did females. However, aggression and plopping behaviours were prevalent in females. The gynandromorphic specimen demonstrated behavioural activities similar to those of a male, including a relatively frequent mate body antennation and an attempt to mount a female. However, it approached the female less frequently in comparison to conspecific normal males, and it did not demonstrate substrate antennation and jumping, typical of Discoelius male mating behaviour. Based on the parameters of the nest cell, the probability of the development of the gynandromorphic specimen from an unfertilized (male) egg was higher than the probability of development from a fertilized (female) egg.

Three new species of Epipompilus Kohl (Hymenoptera, Pompilidae, Pepsinae) from Australia

Three new species are added to the genus Epipompilus (Hymenoptera: Pompilidae) in Australia. Epipompilus mirabundus sp. nov., E. taree sp. nov., and E. namadgi sp. nov. are described and illustrated. A key to males of Epipompilus is provided. A novel association of Epipompilus and Sceliphron formosum (Hymenoptera: Sphecidae) is also documented. The larva of E. mirabundus sp. nov. was found sharing single nest cell with a Sceliphron larva; this association could be the result of a parasitised spider being brought back to the nest by the Sceliphron adult.

Macroscopic and microscopic studies of the nests and the stages involved in the nesting process of Centris muralis Burmeister (Hymenoptera: Apidae: Centridini) bee in the adobe walls, in La Rioja, Argentina

Centris (Wagenknechtia) muralis Burmeister is one of the most common bee species distributed in the xeric region of Argentina. This work describes macro-and micromorphological aspects of the nesting architecture and the stages involved in the process of nesting of C. muralis bee, in the adobe walls of Capayán ruins and recent earthen constructions in Udpinango and Villa Castelli, La Rioja, Argentina. In addition, we discuss the possible factors that may explain the high density of nests observed in the adobe walls of Capayán ruins. These constructions are settled in the northern area of the Monte desert. Our analysis showed that the nest cell walls are strengthened and waterproofed probably by the admixture of organic material to the adobe matrix. Light microscopy of thin sections of the vacated cells showed the inner layers of organic material corresponding to the cocoon, and the outer layer of 0.7 mm thick corresponding to the cell walls consisting mainly of silt and clay, fine sand grains in low rate and absence of grains of sand medium and large. The cell wall was not different in its granulometry from that in the adobe brick, thus suggesting that the cell wall was constructed probably by cementing the particles with bee secretion. The scanning micrographs showed that the cell walls and non-nesting zones exhibited abundant clay crystals in the grain distribution. Pollen from Larrea sp. was observed in high proportions in the nest contents of C. muralis in the Capayán adobe walls.