Showing papers by "Edward O. Wilson published in 1984"
TL;DR: A distinction is made between programmed “elasticity” in the repertory of individual workers and castes and the “resiliency” of the colony as a whole, which depends upon the pattern of caste-specific elasticity.
Abstract: Ten species of Pheidole, representing as many species groups from various localities in North and South America, Asia, and Africa, were analyzed to probe for possible relationships between caste ratios and division of labor. Minor workers are behaviorally almost uniform among the species, but major workers vary in repertory from 4 to 19 behavioral acts (Table 1, Fig. 2). The major repertory size increases significantly across the species with the percentage of majors in the worker force (Fig. 3). This trend is consistent with the basic prediction of ergonomic optimization models under an assumption of colony-level selection. There is also a trend toward reduction of behavioral repertory with increase of size in the major relative to the minor, a second relation expected from theory, but the data are not sufficient to reach statistical significance. When the minor:major ratio was lowered to below 1:1 (from the usual 3:1 to 20:1, according to species), in three widely different species (guilelmimuelleri, megacephala, pubiventris), the repertory size increased by 1.4–4.5X and the rate of activity by 15–30X (Table 1, Figs. 4–6). The change occurred within 1 h of the ratio change and was reversed in comparably short time when the original ratio was restored. This abrupt and important shift in behavior permitted the major workers to serve as an emergency stand-by caste, available to be summoned to a nearly full repertory when the minor worker caste was depleted. The majors also restored 75% or more of the missing minor workers' activity rate under laboratory conditions. Their transformation allowed continued oviposition by the queen and the rearing of larvae to the adult stage. In line with these findings, a distinction is made between programmed “elasticity” in the repertory of individual workers and castes and the “resiliency” of the colony as a whole, which depends upon the pattern of caste-specific elasticity.
256 citations
TL;DR: All of the nine certain or likely social parasites of Pheidole known worldwide are compared, and an anatomical parasitic syndrome is identified through character state analysis, and the evolution is interpreted as having been not only parallel among species but mosaic within species (seetable I).
Abstract: Because social parasites are relatively rare in tropical ant faunas, new or poorly known forms deserve special attention. TwoPheidole species evidently parasitic onP. indica are here described as new species from India (P. lanuginosa, P. parasitica), while a previously known northern South American form,P. microgyna Wheeler, is redescribed and evaluated as a possible parasite ofP. minutula or a closely related host species. Next, all of the nine certain or likely social parasites ofPheidole known worldwide are compared, and an anatomical parasitic syndrome is identified through character state analysis. The nine species appear to be independently evolved. The parasitic character states have tended to evolve within each of these species at different rates, and hence the evolution is interpreted as having been not only parallel among species but mosaic in nature within species (seetable I). In spite of the lesser irregularities in this pattern, an overall trend is evident: the first changes to occur were loss of the worker caste (a loss still incomplete in the overall slightly modifiedP. inquilina), reduction of size, lengthening of the scape, reduction of sculpturing on the body surface, and broadening of the postpetiole. These shifts were followed by reduction of the mandibles and the segments of the funiculus. The generaAnergatides andBruchomyrma, each based on a single extremely advanced species, are placed in synonymy underPheidole. The problematic generaHagioxenus, Parapheidole, andSifolinia are compared withPheidole and their status evaluated. The greater known diversity of parasitic ants in the temperate zones, as compared with the tropics, remains a key problem in the study of ant evolution. Whether the difference is genuine or an artifact of differential sampling cannot be determined until more intensive collecting is undertaken in the tropics.
49 citations
TL;DR: Evidence is reported that the Asiatic representative of the little known ant tribe Basicerotini, Eurhopalothrix heliscata, preys on a variety of termites, but also takes at least some other kinds of insects.
Abstract: 1.
Eurhopalothrix heliscata n. sp. is an Asiatic representative of the little known ant tribe Basicerotini and the first member of the group to be studied intensively. We report evidence that it preys on a variety of termites, but also takes at least some other kinds of insects. Overall, the social behavior is simple relative to that of many other myrmicine ants.
2.
Prey are hunted and retrieved singly. But foraging workers are also able to recruit nestmates to the vicinity of groups of prey and as a result accelerate retrieval of termites to the brood chambers. A prolonged exploration of the surrounding area also ensues.
3.
With the aid of chemical cues, workers are able to recognize material from the vicinity of their nest.
4.
The workers are notably thigmotactic. They use their wedge-shaped heads, hard bodies, and short legs to press into tight spaces. They seize the appendages of termites with their short, sharp-toothed mandibles, clasping these body parts of the prey even more tightly with the aid of their projecting, heavily sclerotized labra.
5.
E. heliscata tend to gather in large, broodless groups away from the main part of the colony. This bivouacing behavior, which effectively dispenses the foragers over a wider area, may improve the efficiency of the predation on termites.
6.
The workers appear not to practice food exchange, worker oviposition, or alarmdefense behavior, nor do they recruit during colony emigration.
7.
Prolonged fighting and dominance-subordinance relations among queens have been observed under laboratory conditions.
8.
Other details of nesting behavior and social interactions are described (see,e.g., table I).
38 citations
TL;DR: The author is joined by a philosopher, a geneticist, and a religion scholar in a discussion of “gene culture co-evolution” and of other issues raised by sociobiology.
Abstract: . The 1981 book Genes, Mind and Culture by Edward O. Wilson and Charles J. Lumsden attempts to offer a comprehensive theory of the linkage between biological and cultural evolution. In the following 21 May 1982 radio broadcast, produced by Julian Brown under the auspices of the British Broadcasting Corporation, Wilson is joined by a philosopher, a geneticist, and a religion scholar in a discussion of “gene culture co-evolution” and of other issues raised by sociobiology. The discussion is introduced and chaired by the editor of Nature, John Maddox.
3 citations
3 citations