Sarah A. Corbet

Bees and the Pollination of Crops and Wild Flowers in the European Community

(1991). Bees and the Pollination of Crops and Wild Flowers in the European Community. Bee World: Vol. 72, No. 2, pp. 47-59.

Insect chemosensory responses: a chemical legacy hypothesis

Abstract. 1. Changes in the chemosensory responses and physiological host tolerance of phytophagous insects and parasitoids may result in new host associations. This paper considers the origin of those changes in ecological and evolutionary time.

Temperature and the pollinating activity of social bees

Abstract. 1 Thermal constraints on flight acivity limit the pollinating effectiveness of bees. Each species of social bee has a microclimatic ‘window’ within which foraging flight can be sustained. 2 To predict whether a given species of social bee is worth testing as a pollinator in a given climate, it is useful to know at least the lower limits of that microclimatic ‘window’. We consider how information from a series of bee counts through a day can be used to characterize a bee species in terms of activity/microclimate relations as a basis for predicting the diel pattern of foraging activity of a bee introduced into a new climate as a pollinator. 3 We discuss the relative merits of bee counts at a foraging patch and counts based on hive traffic as indices of the proportion of bees active. 4 We suggest that the activity/microclimate relations of a species be expressed in terms of the lower threshold black globe temperature for flight activity. Black globe temperature, Tg, is easily measured with inexpensive equipment, and can substitute for measurements of ambient temperature and radiation as a predictor of diel patterns of bee activity. 5 We use examples of field data to explore the relationship between microclimate and activity for the honeybee Apis mellifera and several species of bumblebee, Bombus. Regression analysis is used to relate activity to Tg and to identify the lower temperature threshold for activity from field bee counts. 6 In field studies analysed here, the bumblebees Bombus terrestrisllucorum, B.pascuorum and B.hortorum began foraging at lower temperatures than honey‐bees or B.lapidarius.

Humidity, nectar and insect visits to flowers, with special reference to Crataegus, Tilia and Echium

Abstract. 1. This paper describes field observations on diel changes in the nectars of Crataegus, Tilia and Echium in relation to microclimate and insect visits.

Bee visits and the nectar of Echium vulgare L. and Sinapis alba L.

Abstract. 1. The time‐course of anthesis of Echium vulgare is described.

Butterfly nectaring flowers: butterfly morphology and flower form.

The profitability of butterfly foraging depends in part on the corolla depth and clustering of flowers, and the tongue length, body mass and wing loading of butterflies. Interactions among these attributes of flowers and butterflies were investigated, using data from a field study in Cornwall and from Porter et al. (1992). The maximum corolla depth from which a butterfly can feed depends on tongue length, which correlates with the more easily measured attributes of body mass and wing loading. Small, short‐tongued butterflies did not visit deep flowers. The quantity of nectar sugar per flower necessary for profitable foraging depends on foraging costs, which are expected to correlate with wing loading. Butterfly species with a high wing loading generally confined their visits to flowers that were clustered or very nectar‐rich. Butterfly species with a low wing loading included solitary and less nectar‐rich flowers in their diet. Body mass and wing loading affect a butterflys load‐carrying capacity (limiting the distance between fuelling stops) and cooling rate (limiting the distance between stops for basking or endothermic warming), and will therefore influence the capacity for floral selectivity and for migration and dispersal. Body mass, wing loading and tongue length characterised families or subfamilies of butterflies. For example vanessine nymphalids, with their long tongues and high wing loading, visited the deep, massed flowers of Buddleja davidii, but lycaenids, with their short tongues and low wing loading, did not. These often visited members of the Asteraceae. Eupatorium cannabinum, with massed flowers offering abundant and accessible nectar, was visited by butterflies of all tongue lengths and both high and low wing loading. These findings may help to inform habitat management for butterfly nectaring flowers.

Wingbeat frequency, temperature and body size in bees and flies

ABSTRACT. This paper describes the relationship between ambient temperature and wingbeat frequency in bees and flies of different sizes, and presents new data from insects in free fight. The slope of the relationship changes with the size of the insect, and was different for insects in hovering flight compared with individuals of the same species in forward flight.

Preimaginal conditioning in Drosophila revisited

During metamorphosis, the nervous system of a holometabolous insect changes significantly. Attempts to demonstrate preimaginal conditioning, here taken to mean the retention of learning through metamorphosis, have given mixed results. We used two behavioural assays (the T maze and trap assay) to see whether a change in adult responsiveness could be induced by exposing Drosophila melanogaster larvae to a conditioning stimulus. There was no evidence for preimaginal conditioning from either assay, but the trap assay demonstrated that menthol contamination from the larval environment on the puparial surface could induce a change in adult behaviour. Exposure of adult insects to this contamination could give the appearance of preimaginal conditioning, when in fact the behavioural induction occurred during the adult stage. Young flies responded less strongly than older flies to the odour cues in both assays. This may explain the apparently contradictory findings of some earlier studies of preimaginal conditioning. Copyright 1999 The Association for the Study of Animal Behaviour.

The nesting places of some British bumble bees

SUMMARYThe nest site preferences of British bumble bees were investigated using 432 nest records from a public survey in 1989–91 in which bumble bees were identified to colour groups, each of which contained one or two common and widespread species. Significant differences were found between colour groups in the position of nests relative to ground level, the time of day at which sites were exposed to direct sunlight, and the nature of the immediate environment of the nest sites. Two sizes of wooden artificial domiciles and some made from house bricks and a roofing tile were set out in the field, at or above ground level, over a three-year period. The most frequent occupant was Bombus pascuorum. The proportion of domiciles occupied by bumble bee nests was generally low (average 1.5%), except in one uncultivated garden site. Brick and tile domiciles were cheaper and no less successful than wooden ones, but occupancy rates were too low to reveal any significant differences in acceptability of different bedd...

Forage for bumble bees and honey bees in farmland: a case study

SUMMARYBee visits and the abundance of flowers of different plant species were recorded on a standard walk through UK farmland on 30 occasions in 1989 (the seasonal survey), and in dawn-to-dusk studies. Most of the species visited by bees were perennials. In the seasonal survey (a total of 1 221 bee visits), most visits were made by the long-tongued bumble bee, Bombus pascuorum (447) and by honey bees, Apis mellifera (321). Another long-tongued bumble bee, B. hortorum, was also abundant. The main forage plants important for both long-tongued bumble bee species comprised a seasonal succession of labiates: Lamium album, Stachys sylvatica and Ballota nigra. Plants visited by shorter-tongued bumble bees (B. terrestris/B. lucorum, B. pratorum and B. lapidarius), and honey bees, included Rubus fruticosus agg., Cirsium vulgare, Epilobium hirsutum, Heracleum sphondylium and Brassica napus, and probably other plants outside the survey area. Dawn-to-dusk studies showed that long-tongued bumble bee species were larg...