In what sense can the self-sacrificing sterile ant be considered to "struggle for existence" or to endeavor to maximize the numbers of its descendants? Since the founding of the theory of evolution by natural selection, most biologists have evaded this question by focusing attention exclusively on the colony as the reproducing unit. There is a powerful precedent for this. Darwin himself took this course. He saw only a "minor" difficulty in the evolution of sterility, and he passed over it in a few lines as he proceeded to discuss the "great" difficulty of how the special aptitudes of the workers could be passed on in latent form by their fertile sisters (26). A difficulty over sterility exists, nevertheless, and it is the more surprising that Darwin should have passed over it in that he discussed-but left unsolved-a parallel one raised by the social virtues (courage and self-sacrifice) in man (25). He saw that such qualities would be promoted in intergroup selection but counter-selected within each group. Perhaps the possible avenues of indiscipline in social insects had been so little reported in Darwin's time that the problems they raised were easily overlooked. Darwin's inadequate understanding of heredity may, likewise, have helped to keep the problem out of focus. With better knowledge of heredity and with more facts regarding the social insects to draw upon, Weismann (154) recognized the possible conflict between intergroup and intragroup selection in the evolution of worker attributes. He made the perceptive comment that, "Obviously the workers must be more rapidly improved when all in a hive are progeny of one queen-i.e. they are all alike or almost alike." But this comment was made in the course of discussion of another topic, and he did not pursue the matter. Soon Mendelian genetics resolved Darwin's difficulty of latency, apart from details of mechanism. But the disappearance of this problem does not seem to have given greater prominence to the other, and the question of how worker sterility comes to be selected continued to receive only occasional comment for a long time. Sturtevant (142) in 1938 again outlined it with admirable clarity and with special reference to multiqueened (polygynic) organization, which was by then well known. Rau (118) in 1940 also briefly touched on this crux when he noted how small might be the step separating workerlike behavior in auxiliary Polistes queens 193

Altruism and Related Phenomena, Mainly in Social Insects

I Honeybees of the World.- 1 The Genus Apis.- 2 Stingless Bees (Meliponinae).- 3 Evolution.- 4 Geographic Variability.- 5 Methods of Honeybee Taxonomy: Past and Present.- 6 Morphometric Analysis and Classification.- 7 Apis florea Fabricius 1787: 305.- 8 Apis dorsata Fabricius 1793: 328.- 9 Apis cerana Fabricius 1793: 327.- II The Western Honeybee Apis mellifera L. Classification and Natural History.- 10 Apis mellifera Linnaeus 1758: 576 General Introduction to a Polymorphic Species with an Unusual Range of Adaptation.- 11 The Races of the Near East (Irano-Ponto-Mediterranean Area).- 12 Honeybees of Tropical Africa.- 13 Honeybees of the Western Mediterranean.- 14 Honeybees of the Central Mediterranean and Southeastern Europe.- References.

Biogeography and Taxonomy of Honeybees

Adequate nutrition supports the development of healthy honey bee colonies. We give an overview of the nutritional demands of honey bee workers at three levels: (1) colony nutrition with the possibility of supplementation of carbohydrates and proteins; (2) adult nutrition and (3) larval nutrition. Larvae are especially dependant on protein and brood production is strongly affected by shortages of this nutrient. The number of larvae reared may be reduced to maintain the quality of remaining offspring. The quality of developing workers also suffers under conditions of larval starvation, leading to slightly affected workers. Larval starvation, alone or in combination with other stressors, can weaken colonies. The potential of different diets to meet nutritional requirements or to improve survival or brood production is outlined. We discuss nutrition-related risks to honey bee colonies such as starvation, monocultures, genetically modified crops and pesticides in pollen and nectar.

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Nutrition and health in honey bees

The ecological and genetic correlates of parthenogenesis are clarified by focusing upon two of the major challenges that confront a newly arisen parthenogen: the genetic disruption that results from backcrosses with sexual relatives, and the evolution of a highly generalized genotype. Both of these factors have been ignored in previous theories of the evolution of reproductive systems. Yet, the geographic ranges, ecological characteristics, elevated ploidy levels, and hybrid origins of many parthenogens, as well as the widespread suppression of recombination in automicts, are consistent with expectations derived from the destabilizing hybridization and general-purpose genotype hypotheses. Whereas the support for these hypotheses is broad, much of the evidence is circumstantial; experimental tests would allow an evaluation of the proposed hypotheses and the more traditional alternatives based on differential colonization, competitive, and coevolutionary abilities. An appreciation of the stringent requireme...

Destabilizing Hybridization, General-Purpose Genotypes and Geographic Parthenogenesis

Body size is a key feature of organisms and varies continuously because of the effects of natural selection on the size-dependency of resource acquisition and mortality rates. This review provides a critical and synthetic overview of body size variation in insects from a predominantly macroecological (large-scale temporal and spatial) perspective. Because of the importance of understanding the proximate determinants of adult size, it commences with a brief summary of the physiological mechanisms underlying adult body size and its variation, based mostly on findings for the model species Drosophila melanogaster and Manduca sexta. Variation in nutrition and temperature have variable effects on critical weight, the interval to cessation of growth (or terminal growth period) and growth rates, so influencing final adult size. Ontogenetic and phylogenetic variation in size, compensatory growth, scaling at the intra- and interspecific levels, sexual size dimorphism, and body size optimisation are then reviewed in light of their influences on individual and species body size frequency distributions. Explicit attention is given to evolutionary trends, including gigantism, Cope's rule and the rates at which size change has taken place, and to temporal ecological trends such as variation in size with succession and size-selectivity during the invasion process. Large-scale spatial variation in size at the intraspecific, interspecific and assemblage levels is considered, with special attention being given to the mechanisms proposed to underlie clinal variation in adult body size. Finally, areas particularly in need of additional research are identified.

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Body size variation in insects: a macroecological perspective

Nous avons mis au point des procedures d'analyse discriminante pour identifier les abeilles africanisees et europeennes, qui presentent des ameliorations sur plusieurs points Tout d'abord, la taille des echantillons d'abeilles africanisees et europeennes est beaucoup plus grande et on peut s'attendre a ce qu'ils renferment une plus grande part de la variation des 2 groupes Ensuite, les abeilles europeennes sauvages et les abeilles europeennes elevees commercialement sont bien representees, reduisant ainsi la probabilite de classer en abeilles africanisees des abeilles europeennes relativement petites

https://www.apidologie.org/articles/apido/pdf/1993/06/Apidologie_0044-8435_1993_24_6_ART0005.pdf

Morphometric identification of Africanized and European honey bees using large reference populations

A procedure is described for rapid measurement and identification of honey bees, Apis mellifera L. Parts of bees are slide mounted, and the images are projected optically onto a digitizer tablet that communicates with a computer. Point coordinates for measurements are entered by hand with the digitizer. The computer calculates the various measurements and then determines by discriminant analysis whether the bees are likely to be European or Africanized in origin. The procedure significantly reduces the time and errors in making measurements. Blind tests of field identifications versus analytical identifications agreed in 95.6% of 135 collections. Five other collections with intermediate discriminant scores could have been caused by mixtures of Africanized and European bees, recent hybridization, or unusual environmental stresses that caused a reduction in the size of European honey bees.

Computer-Assisted Measurement and Identification of Honey Bees (Hymenoptera: Apidae)

SYNOPSIS. Two types of parthenogenesis, arrhenotoky and thelytoky, exist in the Hymenoptera. Arrhenotoky, the development of males from unfertilized eggs, is present in all wasps and bees. Thelytoky, the development of diploid females from unfertilized eggs, is present in a few species. Two types of thelytoky, apomixis and automixis, are known. Most thelytokous Hymenoptera are automictic. No meiosis, only mitosis, occurs in apomixis. Meiosis does occur in automixis, allowing crossing-over and segregation of genes. Advantages of thelytoky are that heterotic combinations become fixed, gene loss is reduced, and reproduction requires only a single individual. One advantage of arrhenotoky is that genetic load in males is eliminated. Both environmental and genetic factors contribute to sex-determination in the haplodiploid system of Hymenoptera. Haplodiploidy can facilitate the evolution of social behavior. Parthenogenesis creates some taxonomic problems since thelytokous clones do not fit the generally accepted biological species concept. Some members of bisexual populations probablyacquire thelytoky, forming their own clones, races, or species.

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Systematic and Evolutionary Implications of Parthenogenesis in the Hymenoptera

The western black-legged tick, Ixodes pacificus, is a primary vector of the spirochaete, Borrelia burgdorferi, that causes Lyme disease. We used variation in a 355-bp DNA portion of the mitochondrial cytochrome oxidase III gene to assess the population structure of the tick across its range from British Columbia to southern California and east to Utah. Ixodes pacificus showed considerable haplotype diversity despite low nucleotide diversity. Maximum parsimony and isolation-by-distance analyses revealed little genetic structure except between a geographically isolated Utah locality and all other localities. Loss of mtDNA polymorphism in Utah ticks is consistent with a post-Pleistocene founder event. The pattern of genetic differentiation in the continuous part of the range of Ixodes pacificus reinforces recent recognition of the difficulties involved in using genetic frequency data to infer gene flow and migration.

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Mitochondrial DNA sequence variation in Ixodes pacificus (Acari: Ixodidae)

Ceratina dallatorreana , Friese is native to the Mediterranean region, where both sexes are present. The first bees appeared in the upper Sacramento Valley of California in 1949 and the species has since spread southward to the lower San Joaquin and Santa Clara Valleys. The life history in California is reconstructed by using the structure and contents of the nests, the immature stages, and certain anatomical features of the females, including the amount of wing wear, contents of the gut and spermatheca, development of the ovaries, presence of follicular relics, and the condition of the fat body. The species reproduces primarily by thelytokous parthenogenesis, but rare instances of insemination are detected and 1 male has been collected. Considerable variation in color is present and may be the result of automixis. At least 2 generations a year occur and the adults overwinter in solitary burrows. The nests of the bee are small and have a water-repellent lining which is apparently derived from glands on the second and third sterna. Preference for weedy plants as sources of food and nesting media has contributed to the success of the bee in an area of intense agricultural activity.

Howell V. Daly

Papers

Morphometric identification of Africanized and European honey bees using large reference populations

Computer-Assisted Measurement and Identification of Honey Bees (Hymenoptera: Apidae)

Systematic and Evolutionary Implications of Parthenogenesis in the Hymenoptera

Mitochondrial DNA sequence variation in Ixodes pacificus (Acari: Ixodidae)

Biological Studies on Ceratina dallatorreana, an Alien Bee in California Which Reproduces by Parthenogenesis (Hymenoptera: Apoidea)