John T. Ambrose

The Seasonal Cycle of Swarming in Honeybees

SummaryA six-year study of natural swarming in Ithaca, NY, USA, showed a bimodal distribution for date of swarm emergence, with a peak during the first two weeks in June and a lesser peak during the last week in August and the first week in September. The mean swarm size for 126 swarms was 1·53 kg (11 800 bees). The mean weight of 116 swarm queens was 195·9 mg; of mated queens 203·4 mg, and of virgin queens 185·0 mg. Data from 1976 suggest that a virgin or a young mated queen may accompany a prime swarm.

Diurnal activity, floral visitation and pollen deposition by honey bees and bumble bees on field-grown cucumber and watermelon

SUMMARY Honey bees (Apis mellifera) and bumble bees (Bombus impatiens) were compared for three aspects of pollinating behaviour on field-grown cucumber (Cucumis sativus) and watermelon (Citrullus lanatus). We measured: (1), diurnal foraging activity periods (as related to anthesis); (2), floral visitation rates (number of flowers visited per min by individual foragers); and (3), stigmatic pollen deposition (number of pollen grains deposited on stigmas after single bee visits to female flowers). B. impatiens was more effective than A. mellifera for all three parameters on both crops. B. impatiens initiated foraging activity 15–40 min before A. mellifera; both species continued foraging until flowers closed in early afternoon. B. impatiens consistently visited more flowers per min (P < 0.001) and deposited equal or greater amounts of pollen (P < 0.001) than A. mellifera, particularly during the initial hours of floral anthesis which is when these crops are most receptive to pollination. The data additionally suggest that researchers evaluating different pollinator candidates should consider time-of-day effects when comparing pollen deposition rates between pollinators, as time-of-day had a marked influence on pollen deposition in these studies.

Random Partial Reinforcement in the Honeybee: Effect on Asymptotic Performance and Resistance to Extinction

SummaryHoneybees trained on a random, partial reinforcement schedule as opposed to a continuous reinforcement schedule, and subsequently subjected to extinction conditions, exhibited behaviour similar to that of vertebrates under the same conditions. This behaviour included higher asymptotic response levels and increased resistances to extinction. The results lead to the hypothesis that species of plants which force bees to visit more flowers through partial reinforcement may be more efficiently pollinated than those providing continuous reinforcement, at least under the conditions specified in this work.

Foraging Behaviour of Honeybees on Golden Delicious Apple

SummaryEarlier work had demonstrated that in mixed plantings of Delicious and Golden Delicious apple (Malus domesticus Borkh), the flower structure of Delicious influenced the foraging behaviour of honeybees on Golden Delicious flowers, thereby reducing pollination efficiency. In an orchard composed of Golden Delicious alone, the ‘sideworking’ foraging behaviour observed in mixed plantings was not observed.

Effects of Partial Reinforcement on Recruiting Behaviour in Honeybees Foraging Near the Hive

SummaryThe recruiting behaviour was investigated of honeybees whose inclination to forage received one of three levels of partial reinforcement, or continuous reinforcement, at feeding dishes. Honeybee foragers receiving an intermediate level of partial reinforcement recruited more new workers than foragers receiving either continuous reinforcement or less rewarding levels of partial reinforcement. It is suggested that the evolution in some plants of intermediate levels of partial reinforcement (by their nectar production) ensured maximal pollination, both by its direct effect on foraging behaviour and also indirectly by stimulating recruiting behaviour in the foragers.