Effects Of Multiple Mating Research Articles

Effects of multiple mating on reproduction in female thirteen-lined ground squirrels

Effects of multiple mating on reproduction in female thirteen-lined ground squirrels

The effects of multiple mating on the worker-queen conflict in Apis mellifera L.

A deterministic model is presented which shows that multiple mating reduces the conflict between workers and queen in the optimal investment ratio in each sex. The natural risk of the nuptual flights of honeybee queens fits well into the theoretically determined risk when queens tend to optimize the numbers of drones with which they mate.

The effect of multiple mating on genetic relatedness in larval aggregations of the imported willow leaf beetle (Plagiodera versicolora, Coleoptera: Chrysomelidae)

The effect of multiple mating on the average genetic relatedness within socially interacting sib groups was studied in the imported willow leaf beetle. Using an electrophoretically determined genetic marker, it was demonstrated that between 49 and 96% of wild caught females produce egg clutches expressing multiple sires. Following theoretical predictions of Wade (1982), this information was used to estimate the harmonic mean number of sires per family and then the average relatedness within families. Average relatedness was estimated to be 0.38. An alternate form of data analysis suggested by Pamilo and Crozier (1982) did not require any knowledge of paternity and resulted in a slightly higher estimate of relatedness, 0.44.

Multiple mating and the evolution of social behavior in the hymenoptera

The data on the frequency of mating by queens of eusocial Hymenoptera are reviewed. It is pointed out that the issue of sperm clumping is probably irrelevant to the evolution of eusociality. The hypothesis is presented that multiple mating is an adaptation for maintaining large colonies. In ants there is a significant relation between the size of the colony and the frequency of mating. The effect of multiple mating on the spread of a gene for worker behavior is explored. If a female mates twice, the effective number of matings is less than two except in the case of identical sperm contribution by the males. Sperm bias is defined as the contribution of unequal amounts of sperm by the males that mate with a queen. Sperm bias can be produced as a sampling phenomenon, by inter-male competition for females and by sperm competition. The relation between the ergonomic efficiency of the workers at the production of reproductives and the number of matings that is consistent with the evolution of eusociality is derived. If workers are only about 10% more efficient at producing reproductives within a eusocial colony than they are solitarily, then two matings by the queen will still produce a selective advantage to eusocial behavior.

The Effects of Multiple Matings on Fertilization Capability in Male American Toads (Bufo americanus)

The Effects of Multiple Matings on Fertilization Capability in Male American Toads (Bufo americanus)

Studies of sperm competition in two species of muroid rodents

1. In three experiments on the effects of mating order, wild-type male deer mice, Peromyscus maniculatus bairdi were tested in competition with brown recessive, wide-band agouti, and blonde mutant males. Females of the homozygous recessive genotype received two ejaculatory series from a male of each genotype; mating order was varied. There were no significant effects of mating order on litter composition. In a parallel experiment wild-type and albino male prairie voles, Microtus ochrogaster, mated for one ejaculation each with albino females. There was a significant advantage with respect to litter composition for the male ejaculating last. Together with data from other species, these results suggest that effects of mating order are highly species-specific and must be evaluated for each species before speculations are made regarding the effects of multiple matings. 2. Males of various genotypes differed with respect to differential fertilizing capacity. Wild-type male deer mice outcompeted both brown recessive and wideband agouti males. The combinations of blonde and wild-type deer mice and albino and wild-type prairie voles yielded strain differences in litter composition in one mating order but not in the other. Counts of the numbers of sperm from males of different genotypes in the uteri of females revealed no sigificant strain differences. Thus, strain differences are not simply a function of sperm numbers. 3. Female deer mice mated or exposed to more than one male had a lower probability of pregnancy than those mated for comparable numbers of ejaculations with one male in previous studies. Additional data on pregnancy initiation in females of the brown-recessive genotype mated with one male revealed them to be only slightly less likely to become pregnant than wild-type females. Strain of male had little effect. 4. No significant effects on litter composition were attributable to the length of the delay between matings by successive males. This was established both via correlational analyses of the data from the mating order studies and in an additional experiment in deer mice in which delays of 2 h were imposed between the last ejaculation by the first male and introduction of a second male. 5. Litter composition in deer mice reflects the number of ejaculations attained by each of two males. In one experiment, female deer mice mated first with a blonde male and then with a wild-type male. The blonde male delivered three ejaculations and the wild-type male one ejaculation in one condition and the wild-type male three ejaculations and the blonde male one in the other. Litter composition was significantly affected.

The Influence of Multiple Mating On the Reproduction and Genetics of Heterodera Rostochiensis and H. Schachtii

Females of Heterodera rostochiensis Woll. embedded in agar or peat were inseminated more readily than in sand. Females removed from their host plants with small pieces of root attached lived longer and produced more eggs than those taken from roots. The behaviour of males in the presence of females was observed, or was deduced from tracks left on an agar surface or from their behaviour towards attractant substances secreted by the females and absorbed in agar discs. Males of H. rostochiensis attracted each other slightly but were much more strongly attracted to females. When females were in groups, males at a distance responded to the group as a whole, rather than to individuals, but when near to the group they tended to be 'captured' by a single female near the edge of the group. To estimate the proportions of ineffective males and sterile females in matings and the influence of multiple matings on fecundity, females were mated with different numbers of males. Males of H. rostochiensis and H. schachtii Schm. seemed able to inseminate up to ten females. Fecundity depended more on the age of the females when taken from the roots than the number of males that inseminated them. When several males collected around a single female they obstructed each other in attempts to copulate, but several must have succeeded in inseminating the female, counteracting the loss of fecundity caused by sterile or impotent males of which there were many. The genetic effects of multiple matings on inheritance were explored theoretically, using as an example the ability of some larvae of H. rostochiensis to become females in the roots of eelworm resistant potatoes bred from Solanum tuberosum ssp. andigena. Kort's data from single cyst cultures seemed to fit the theory that this ability depended on a recessive gene occurring infrequently. It seems that neither the first nor the last mating was the only effective one and multiple mating would cause a greater diversity of genes in the offspring of one female. Promiscuity and the ability of males to mate several females successfully, are advantageous in species such as H. rostochiensis and H. schachtii, in which the sex ratio ranges greatly and males may be outnumbered nine to one in sparse populations. Because eggs are concentrated in cysts, the progeny from cysts tend to invade roots in groups and clusters of females result. Grouping enhances their attractiveness to males. The males leave the females they have recently mated, move away and so have the opportunity of fertilising others.

Theory of Control of Insect Populations by Sexually Sterile Males

The theory of control of insect populations by the release of sexually sterile populations or by treating field populations is examined by establishing basic premises and deriving algebraic equations. The effect of multiple mating is shown to depend on the fertility of females mated to both sterile and fertile males. The effect of release of males alone will be the same as release of both males and females when the released females are sterile; the effect of release of females alone will depend on the number of times males can mate. If a population is seasonally cyclic, the timing of initial releases will have no effect on the number of sterile adults or the time required for extermination, but the initial reduction will be greater and the population before extinction will be lowered if releases are started when the increment of increase is least. The increment of increase of a population and the factors determining the increment are important in determining plant capacity and cost of control. When the cost of the rearing plant, the cost of operation, and the number of generations required to reach extinction are considered, we appear to have an optimum size of plant and rate of release; higher rates of release are costly and save little time. Sterilization of the males in a natural population is a more effective method than the release of sterile populations if both males and females are killed or sterilized. The relative efficiency of different treatments of the 2 sexes in the field depends on the mating ability of the males, the proportion of the 2 sexes that survive treatment, and the fertility of the survivors.