The primitively social sweat bee, Lasioglossum zephyrum, blocks the entry into its nest of most conspecifics from other colonies. Laboratory inbreeding of these bees produced lines which showed a positive linear relationship between the coefficient of relationship of bees tested and how often they permitted non-nestmates to pass them. The most probable mechanism is a genetically determined odor coupled with a learned component by which guard bees discriminate between odors of close kin and other bees.

No abstract

No abstract

The oral toxicity of boron compounds to the Argentine ant, Linepithema humile (Mayr), was evaluated in laboratory tests. The ants were provided 25% sucrose water containing 0.5 and 1% boric acid, disodium octaborate tetrahydrate, and borax. Lethal times of these solutions were a function of the concentration of boron. In field tests, the ants showed no discrimination between disodium octaborate tetrahydrate and boric acid. There was a significant reduction in consumption of sucrose water with > 1% boric acid.

No abstract

The sex attractant pheromone produced in mandibular glands of queens of the slave-making ant Polyergus breviceps has been identified as a blend of methyl 6-methylsalicylate and 3-ethyl-4-methylpentanol. In field trials, each compound alone was completely unattractive to males, whereas blends of the two compounds attracted hundreds of males within a couple of hours.

No abstract

The Ctenoplectridae (for the genera Ctenoplectra and Ctenoplectrina) are separated from the Melittidae, in which they have commonly been included. Ctenoplectrids differ from melittids in many characters, and are more closely related to the long‐tongued families Fideliidae, Megachilidae, Anthophoridae, and Apidae than to the Melittidae and other short‐tongued families. Ctenoplectrids are the sister‐group of the long‐tongued bees (and could be considered as long as long‐tongued bees with labial palpi of short‐tongued bees); melittids are the sister‐group to the ctenoplectrids plus long‐tongued bees. Characters are listed that support these relationships. Ctenoplectra species appear to be oil collectors from flowers of curcurbits. Some behavioural observations are included. Ctenoplectrina is a probable parasite in nests of Ctenoplectra, as it lacks the pollen and oil manipulating apparatus.