Showing papers by "Andrew J. Beattie published in 1991"
TL;DR: While mutualism is thought to be a common type of species interaction, there is still little evidence for this belief.
Abstract: A great number and variety of interactions are widely assumed to be mutualistic because the species involved exchange goods or services from which they appear to derive benefit. A familiar example is pollination, in which animal vectors receive food in the form of nectar and/or pollen, while the ovules of plants are fertilized. Unfortunately, most studies fail to demonstrate that both participants benefit in any significant way and therefore lack the information necessary to determine whether a given interaction is mutualistic. While mutualism is thought to be a common type of species interaction, there is still little evidence for this belief.
129 citations
TL;DR: While ant foraging was restricted, some outcrossing occurred and in the absence of clonality it is likely that ant foraged would have yielded a mixed mating system similar to those reported for a wide array of insect pollinators.
Abstract: The self-compatible orchid Microtis parviflora is pollinated by the flightless worker caste of the ant Iridomyrmex gracilis. The orchid is clonal and forms small patches, usually less than 1 m2 , of disconnected individual ramets. Ant pollinators visited and revisited a limited proportion of available inflorescences, and 40% of all flower visits occurred within plants promoting self-pollination. Pollen labels indicated that self-pollination accounted for 51% of the pollen transfers, although pollen carryover extended beyond 16 flowers on 2 or 3 inflorescences. The distribution of ant movements between plants was leptokurtic with a mean of 12.4 ± 14.9 cm and a maximum of 89 cm, but a high proportion of movements were within clones accentuating the level of self-pollination. However, some pollen transfers between inflorescences of unlike genotypes contributed to a low incidence (max = 8%) of outcrossing. In 12 patches examined by electrophoresis, the density varied from 11 to 61 inflorescences per m2 and a maximum of only 4 genotypes were detected. Electrophoretic analysis revealed populations were highly inbred: only 23% (N = 17) of the loci were polymorphic and the mean gene diversity h, was 2.7%. Heterozygotes were observed in only one population given a mean fixation index F, of 0.982. These results reflect the combined effects of restricted ant foraging and clonality. Nevertheless, while ant foraging was restricted, some outcrossing occurred and in the absence of clonality it is likely that ant foraging would have yielded a mixed mating system similar to those reported for a wide array of insect pollinators. Given the ability of ants to generate pollen flow, the reasons for the rarity of ant pollination appear to lie elsewhere.
92 citations
TL;DR: Differential integumental effects on pollen are consistent with the relative abundance of bee, wasp and ant pollination systems, particularly the extreme rarity of pollination by ants.
Abstract: Antibiotics on the surface of ants inhibit pathogenic microorganisms and significantly lower pollen viability. However, the viability of pollen in contact with the integument of Apis mellifera L. and Vespula germanica (F.) is not significantly lowered. Trigona carbonaria Smith induces some reduction in pollen viability and this may be the effect of resins harvested for nest construction. The disruption of pollen function by T. carbonaria is much less severe than that produced by ants. Differential integumental effects on pollen are consistent with the relative abundance of bee, wasp and ant pollination systems, particularly the extreme rarity of pollination by ants.
19 citations
TL;DR: As one-week-old bees did not respond to isoamyl acetate and 2-heptanone as quickly as the older bees, it is suggested that for the first week of life, these compounds do not function as alarm substances.
Abstract: SUMMARYSound responses by caged 1-, 2- and 3-week-old worker honey bees (Apis mellifera) to two bee alarm substances (isoamyl acetate and 2- heptanone), two components of the Nasonov gland pheromone (citral and geraniol), and two odoriferous compounds (methyl benzoate and trans-cinnamaldehyde), were recorded and analysed. The mean frequency of worker bee sound responses to the alarm substances was easily differentiated statistically from all the others.The adaptive significance of the differential sound response to alarm substances remains unclear. As one-week-old bees did not respond to isoamyl acetate and 2-heptanone as quickly as the older bees, it is suggested that for the first week of life, with respect to acoustic responses, these compounds do not function as alarm substances.
3 citations