Reproductive potential and nesting effects of Osmia rufa (syn. bicornis) female (Hymenoptera: Megachilidae)

Abstract

A b s t r a c t The red mason bee Osmia rufa is a solitary bee belonging to the family Megachilidae, and is prone to nest in aggregations. Each female builds a nest separately in pre-existing cavities such as holes in wood and walls or empty plant stems. This is done by successively setting the cells in a linear series. In this study, we elucidate the nesting behavior and the reproductive potential of a single O. rufa female. The reproductive potential of nesting females was evaluated after the offspring finished development. We observed that an individual female may colonize up to five nest tubes and build 5-34 cells in them (16 on an average). During the nesting time the number of cells decreased with the sequence of nest tubes colonized by one female, which built a maximum of 11 cells in the first occupied nest and 5 cells in the last (fifth nest). Our observations indicated that 40% of nesting females colonized one nest tube as compared to 7% colonizing five nest tubes. Furthermore, in subsequent nest tubes the number of cells with freshly emerged females gradually decreased which was the reverse with males. Thus, the sex ratio (proportion of male and female offspring) may change during the nesting period. The female offspring predominated in the first two nesting tubes, while in the subsequent three tubes male offspring dominated. We also cataloged different causes of reduction in abundance of offspring in O. rufa females such as parasitization or problem associated with moulting.

Plant–insect interactions: the role of ecological stoichiometry

“…As a model pollen eater, the mason bee Osmia bicornis Linnaeus 1758 (= Osmia rufa Linnaeus 1758; Hymenoptera, Megachilidae) will be used. Osmia bicornis larvae feed directly on unprocessed pollen provided by their mother to the nest [105,106]. Direct comparisons of the elemental composition of pollen with the composition of adult bodies and empty cocoons can identify stoichiometric mismatches and thus nutritional constraints, thereby providing the first hint for potential solutions that can be applied to overcome such limitations.…”

When beggars are choosers—How nesting of a solitary bee is affected by temporal dynamics of pollen plants in the landscape

“…Such results have been documented for leafcutter bees Megachile rotundata and M. apicalis (Kim, ; Peterson & Roitberg, ). Similar to leafcutter bees, Osmia lay female eggs before male ones (Giejdasz et al., ; Raw, ) and female larvae require a larger pollen provision for development compared to males (Radmacher & Strohm, ; Seidelmann, ). A large production of female offspring would therefore benefit from timing of the bee's phenology to abundant pollen resources in early season.…”

“…The reason may be that the period of laying female eggs extends beyond flowering of oak. Osmia bicornis nests can indeed be initiated with female eggs throughout the nesting season, although the proportion of females per nest has been shown to decrease with time (Giejdasz et al., ). We found a nonsignificant trend for the number of female offspring per site to be positively affected by the interaction of oak with buttercup; that is, female offspring showed the same response to flower resources as did the total number of offspring.…”

“…Eggs are laid in sequence, in separate brood cells together with a provision of pollen and sealed with loam, to form a gallery of 10–20 cells. A female may construct several nests, and the proportion of female eggs is higher in nests constructed at the beginning of the nesting period, compared to nests constructed later (Giejdasz et al., ). Females (larvae, pupae, and adults) are larger than males and require more pollen for development (Radmacher & Strohm, ; Seidelmann, ).…”

“…have protandrous emergence (males emerging before females). Such species lay female eggs at the back of nests and predominantly early in the season and then male eggs later and toward the nest opening (Giejdasz, Fliszkiewicz, Bednářová, & Krishnan, ; Torchio & Tepedino, ). Female bees are larger than males and require more pollen per egg for development (Radmacher & Strohm, ).…”