Factors affecting offspring body size in the solitary beeOsmia bicornis(Hymenoptera, Megachilidae)

Abstract

Body size is related to fitness in many insects. In solitary bees offspring body size is largely determined by maternal provisions and microclimate. We studied the effect of quantity and quality of provisions and rearing temperatures (20, 25 and 30 • C) on body size in the Red Mason bee, Osmia bicornis. Cocoon weight increased with provision weight and decreased with increasing temperature. High temperature (30 • C) led to high mortality of larvae and smaller body size, partly due to incomplete consumption of the provisions. Diversity of pollen in the provisions was low, and most provisions primarily consisted of mainly oak and maple pollen. Pollen diversity did not affect cocoon weight and males provided with pure oak or pure maple pollen showed similar adult size. Our results suggest that the quantity of provisions and temperature, but not pollen quality influence the development of O. bicornis progeny and might affect population dynamics of this abundant European pollinator. Osmia bicornis / body size / pollen diversity / temperature

Effects of constant and fluctuating temperatures on the development of the solitary bee Osmia bicornis (Hymenoptera: Megachilidae)

“…In general, our results on the effects of temperature on prepupal weight are consistent with the temperature-size rule (Atkinson 1994) and a previous study on O. bicornis which revealed a strong decrease in body size with increasing constant rearing temperatures (Radmacher and Strohm 2010). However, bee offspring in the 22.5°C treatment had an unexpectedly low prepupal weight.…”

“…We were not able to explain this finding since the 22.5°C treatment was treated in the same way as the others. Regarding the 17.5°C and 27.5°C treatment, the decrease in body weight was not as pronounced as in a previous study (Radmacher and Strohm 2010), where overall warmer temperatures (20°C, 25°C, and 30°C) were used and the weight of adult bees inside their cocoons was determined.…”

“…Since the body size of O. bicornis depends largely on the provision weight (Radmacher and Strohm 2010), we used the ratio of prepupal weight to provision weight as a measure for body size to correct for individual differences in provision weight. ANOVAs (PASW Statistics 18 (i.e.…”

Toxicity of Spirotetramat on Solitary Bee Larvae, Osmia Cornuta (Hymenoptera: Megachilidae), in Laboratory Conditions

“…These bees can remain in the prepupal stage for more than one year without any apparent difference, but they can then resume their development when exposed to warmer temperatures (Sgolastra et al, 2012). On the other hand, the larval mortality increases at higher temperatures (Bosch and Kemp, 2000;Radmacher and Strohm, 2010). For these reasons, the optimal test temperature should be between 24°C and 26°C.…”

Colony pollen reserves affect body size, sperm production and sexual development in males of the stingless bee Melipona beecheii

“…nutritional content of pollen) of resources available for feeding the immatures can affect the size of the resulting adults. This holds for mass provisioning species as well as for progressive provisioners, and for solitary as well as social species (Roulston and Cane, 2000;Radmacher and Strohm, 2010;Quezada-Euán et al, 2011). In the case of social bees, the colony's nutritional conditions under which males are reared may also be important for successful development, given that spermatogenesis occurs during the pupal stages and is usually completed at and after the emergence of the imago (Pereira-Lima et al, 2006).…”