Wing Wear Research Articles

Comunidade de machos de Euglossinae (Hymenoptera: Apidae) das matas ciliares da margem esquerda do médio Rio São Francisco, Bahia

As flutuações de abundância e riqueza sazonais, a estimativa de períodos de emergência a partir da idade dos indivíduos capturados e a preferência por químicos atrativos foram estudados pela atração de machos de Euglossinae às iscas-odores. Os Euglossinae foram amostrados nas matas ciliares do povoado de Ibiraba (10º 48' S e 42º 50' W), semi-árido da Bahia, entre setembro de 1996 a julho de 1997. Os machos atraídos às essências foram capturados com rede entomológica e com armadilhas. Foram capturados 527 indivíduos de sete espécies e três gêneros. Eucaliptol foi a essência mais eficiente, atraindo machos de todas as espécies e 87,9% dos indivíduos, seguido por baunilha, benzoato de benzila e eugenol; salicilato de metila não foi atrativo. Os machos foram mais abundantes entre maio e julho, meses imediatamente posteriores ao período de chuvas. Euglossa cordata L., Euglossa fimbriata Rebêlo & Moure e Eulaema nigrita Lepeletier foram as espécies mais abundantes, representando 97,2% do total de machos amostrados. Euplusia melaena Moure sp. n., Euglossa securigera Dressler, Euglossa melanotricha Moure e Euplusia aridicula Moure & Neves sp. n. contribuíram com apenas 2,8% dos indivíduos coletados. Machos jovens (sem desgaste alar) foram os mais abundantes, estando presentes durante todo o ano.

Fragrance Collection, Storage, and Accumulation by Individual Male Orchid Bees

Individually marked males of two species of Euglossa were sighted repeatedly and over considerable periods of time (up to 44 days) at artificial fragrance baits exposed on Barro Colorado Island (BCI), Panama. Individuals switched between different bait chemicals that are attractive for the respective species, and no bait preferences or individual bait constancy was observed. GC-MS analyses of 153 males of three species showed that individual hind tibiae contain highly variable quantities of a complex and species-specific blend of fragrance compounds, mainly terpenoids and aromatics. In all three species, frequency distributions of individual quantities were strongly skewed towards individuals with small amounts, and individual amount and complexity were positively correlated. Tibial contents of male Euglossa imperialis that were kept alive in a flight cage for 0, 5, 10, or 15 days showed no qualitative or quantitative change over time, suggesting that the fragrances are very efficiently stored in the hind legs. In Euglossa cognata wing wear, an established age correlate of the species, was positively correlated with individual fragrance quantity. Our results suggest that male euglossines forage continuously for a variety of volatiles, store them, and finally acquire large quantities of a complex and specific fragrance bouquet. Both qualitative and quantitative aspects of individual contents are likely to contain information on male phenotypic and genotypic quality.

Sexual Behavior of Acanthocephala declivis guatemalana (Hemiptera: Coreidae) and the Allometric Scaling of their Modified Hind Legs

The sexually dimorphic hind legs of Acanthocephala declivis guatemalana are used for different functions in males and females, and they scale differently on body size. The hind legs of males are used to deliver powerful squeezes to other males in battles at feeding and mating sites, and the diameter of the hind femur and the length of its large tooth are proportionally larger in large males compared with other body characters. The largest tooth on the female hind femur probably functions in the less forceful female–female battles, and it is also proportionally larger in large females. However, neither the female hind tibial plate, which is used as an aggressive signaling device, nor the diameter of the female hind femur are proportionally larger in large females. Wing wear and breakage of hind leg spines, combined with behavioral observations of marked bugs, indicate that the breeding system combines elements of resource defense polygyny and lek polygyny. Females mate more than once, despite the attendant cost of reduced feeding opportunities.

Post-Stinging Behavior of Worker Honey Bees (Hymenoptera: Apidae)

Following sting autotomy, honey bee workers continue to participate in colony defense by following and harassing potential predators. Bees that pursue a human observer are highly likely to have previously stung a leather target at the colony entrance, Wing wear and other characteristics of the pursuing bees suggest that they are soldier or guard bees rather than foragers or younger bees. We compared the responses of different behavioral castes by inducing a bee to sting and then assessing the response of that bee to other bees; after stinging, guard bees displayed heightened activity, but soldiers, foragers, or hive bees did not. Removal of the sting in cold-narcotized bees showed that the physiological stimulus for pursuit behavior was not solely the removal of the sting. The continued defensive role for bees that have lost their sting retains the residual value of individual workers to the colony.

Egg Limitation, Host Quality, and Dynamic Behavior by a Parasitoid in the Field

Patterns of host selection and host use by insects with parasitic lifestyles are predicted to be fundamentally dynamic, responding to environmental conditions and physiological states. A particularly robust prediction is that the number of mature eggs that a female carries (her “egg load”) should influence behavior. As egg load decreases, females are predicted to exhibit increasingly selective host use patterns. We tested the hypothesis that egg load and host size influence the behavior of the parasitoid wasp Aphytis aonidiae attacking the armored scale insect Quadraspidiotus perniciosus. Aphytis females can use hosts either for oviposition or for adult “host feeding,” which is the consumption of host material by adult parasitoids. Theory predicts that host feeding should be (i) favored by low egg loads and (ii) more prevalent on lower—quality (smaller) hosts. We conducted observations of individual females foraging freely in the field to determine whether hosts were used for oviposition or for host feeding. As predicted by theory, the likelihood that a host was used for oviposition (as opposed to host feeding) increased with both parasitoid egg load and host size. Thus, parasitoids exhibited higher host—selectivity at lower egg loads. Since egg load and a parasitoid's experience with hosts were not experimentally separated, the egg load effect could in principle have been either direct or indirect and operating through a correlation with experience. In either case, this result constitutes the first demonstration of a link between physiological state and oviposition behavior by a parasitoid in the field. Parasitoid age, as measured using a wing wear index, did not influence behavior. A laboratory study revealed that the relationship between a host's size and the size and initial egg load of the parasitoid developing on that host was positive, but that it followed a pattern of diminishing returns. No effect of host size on behavior could be detected over the range of host sizes that were within the asymptotic region of this relationship.

Male size and survival: the effects of male combat and bird predation in Dawson’s burrowing bees, Amegilladawsoni

1. Males of Dawson’s burrowing bee, Amegilla dawsoni, occur in two size classes, large majors and small minors. Major males compete aggressively for emerging females in completely exposed emergence areas, whereas minors often employ an alternative mating tactic, which involves rapid patrolling in the vegetated periphery of emergence areas.2. Because major males wrestle violently with rivals on the ground, they experience greater wing wear and a higher risk of wing damage than minor males. In addition, males patrolling emergence areas and waiting on the ground for emerging females are more likely to be killed by predatory birds than are peripheral minors.3. Measurements of longevity based on mark–recapture data suggest that majors are slightly shorter‐lived than minor males. If male–male combat and predators do reduce the lifespan of major males relative to minors, the effect would be to decrease the lifetime mating advantage of majors relative to minors.4. Differential mortality could therefore be a factor in the maintenance of the two forms of males in this species.

Effects of seasonal variation in operational sex ratio and population density on the mating success of different sized and aged males in the yellow dung fly,Scathophaga stercoraria

In the yellow dung fly, Scathophaga stercoraria, large males generally enjoy higher short–term mating success than small males. This paper examines how the large male mating advantage is affected by the natural variation in operational sex ratio (OSR) and population density or by the relationship between male size and age. There were seasonal changes both in the number of males per pat (range 1–93 males) and in OSR (0.24–1.34, females/males). The mean size of copulating males and males guarding ovipositing females was larger at pats with a large number of rival males. Variance in male size within pats increased with OSR but was unaffected by the number of males. The number of males per pat decreased and OSR became more female–biased towards the end of the flight season. Both the intensity of selection on male size and the opportunity for selection decreased with season. The proportion of young males (no wing wear) did not differ between single, copulating or female guarding males. Except at the beginning of the flight season, large mating males were younger than small ones, which may have resulted from either different patterns of adult mortality or dispersal. While these results confirm that large males in general enjoy higher short–term mating success than small ones, they also show that small males are successful at pats with a low number of rival males and a female–biased OSR. Age differences between mating males of different size suggest that short–term mating success does not correspond to lifetime mating success. Variation in sexual selection on male size and the possible differences in lifespan of different sized males could be among the factors maintaining genetic size variation in this species.

Local Dispersal by the Cinnabar Moth Tyria Jacobaeae

We used mark‐recapture data to measure and model movement by the adult stage of the cinnabar moth Tyria jacobaeae (Lepidoptera, Arctiidae). Our objectives were: (1) to standardize the description of cinnabar moth movement and thereby provide a more reliable basis for comparison and extrapolation, and (2) to screen the potential influence of gender, physical condition, time, spatial location, and spatial heterogeneity in the environment on movement parameters. Recapture rates depended on wing wear (low 16%, high 11%) but were independent of behavior immediately after release (mobile 15%, immobile 14%), gender (male 13%, female 16%), or location in the study area (central 15%, peripheral 15%). Thus, mortality and/or emigration was greater for individuals with high wing wear compared to those with low wing wear. Moths were aggregated at the southwest margin of the study area both at initial capture and recapture. The direction of movement was biased in north and south directions, perhaps because forests on the east and west boundaries created a corridor channeling movement. The movement observed within a single generation did not conform to simple diffusion, which predicts that the mean square displacement (MSD) increases linearly with time. Instead, observed movement rates varied over time, and the relationship between MSD and time varied by gender, smoothly decelerating in males and erratically increasing in females. Observed movement (represented by the frequency distribution of displacements x for each time t with time measured at a daily resolution) was adequately approximated by a Weibull distribution, for which estimates of the shape and scale parameters were calculated. Male distributions were more frequently mounded, associated with higher values of the shape parameter α, and the scale of male distributions shifted sooner to longer distances, associated with higher values of the scale parameter β. The Weibull parameters varied by sex and time, suggesting that males were initially more mobile than females, but the magnitude of the difference varied over time. The speed and direction of individual movement were independent of the moth's spatial location within the field. We conclude that (1) movement speed depended on gender and time, while movement direction was related to spatial heterogeneity in the environment, and (2) much of the disagreement about movement rates among studies of the cinnabar moth can be related to researchers taking measurements and drawing inferences on different scales of observation, and therefore arriving at conflicting results.

Energy Reserves and Mating Success in Males of the Yellow Dung Fly, Scathophaga stercoraria

1. Carbohydrate (glycogen, fructose and other sugars) and lipid contents of mate-searching males were analysed in the Yellow Dung Fly, Scathophaga stercoraria. Males were classified into three relative age classes according to wing wear. 2. Fructose content increased towards the afternoon suggesting that males feed on nectar during the daytime. 3. Both carbohydrate and lipid contents were positively related with male body size. When controlled for body size, males that caught a female contained more glycogen and fructose as compared to males that failed to do so within each age class. 4. Among males copulating with a female, males on cow pats differed significantly from those in the surrounding grass by having more glycogen, sugars and lipids. 5. The results suggest that males successful in mate searching are in a better energetic condition than unsuccessful males. Energy acquisition can be an important component of mating success in species where mate searching involves frequent flying.

Mating and nectar feeding in the psychomyiid caddis flyTinodes waeneri

The psychomyiid caddis fly Tinodes waeneri (L.) mated on a shrub near the shore‐line (and the littoral emergence site) and on adjacent flowers. Both males and females were shown to ingest nectar, from different species of flowers having open nectaries (mostly of the family Apiaceae). Male fat content was negatively correlated with age (wing wear), indicating that ingested nectar did not restore lipids. Therefore, we presume that nectar was mainly used for mechanical activities (e. g. flying, walking, mating). A male lost about 7% of his original carbon and nitrogen during copulation, suggesting that they had the potential to copulate often. The sex ratio differed between the shrub and flower habitats, and females on flowers were also older and had more frequently laid eggs. Thus, females seemed to mate as virgins on the shrub, deposited their first egg batch, returned to the shore, ingested nectar from the flowers and copulated again. Males on flowers encountered proportionally more females, but those fem...

A method for estimating the age of bees: Age-dependent wing wear and coloration in the Wool-Carder beeAnthidium manicatum (hymenoptera: Megachilidae)

A method for estimating the age of bees: Age-dependent wing wear and coloration in the Wool-Carder beeAnthidium manicatum (hymenoptera: Megachilidae)

Nest re-use and communal nesting inMicrothurge corumbae (Hymenoptera, Megachilidae), with special reference to nest defense

Observations on the nesting activities ofMicrothurge corumbae, carried out at the University Campus of Ribeirao Preto, Sao Paulo, Brazil, from 1977 to 1981, indicated that 61.9 % of nests were re-used by succeeding generations. Re-use by one generation was more frequent than by two generations, and re-use by a third was observed only once. Nests were re-used by one or several females. Single females were more frequently in the first re-use. In these cases nest re-use did not differ essentially from the solitary foundation of a new nest, except for the adoption of a pre-existing nest without excavation. In multifemale nests, analysis of relative age (wing wear), ovarian and spermathecal conditions of associated females and the content of nests at excavation indicated that the social pattern in such colonies is communal. There is some evidence that the associated females are relatives. The chalcidoid waspLeucospis was the principal nest parasite, and ants of the genusCrematogaster were nest predators. In multifemale nests, the rate of parasitism was significantly lower than in solitary nests, indicating that nest-sharing resulted in improved nest defense. On the other hand, the absence of predation on immatures of the first generation of M.commbae in multifemale nests suggests that such nests are also more resistant to attack by predators.

Morphological Senescence and Longevity: An Experiment Relating Wing Wear and Life Span in Foraging Wild Bumble Bees

1. The insect wing appears to degenerate with use, so that wing wear increases with increased flight activity. Wing degeneration may affect an insect's mortality. 2. The rate of mortality is known to increase with age in worker bumble bees. This study examines whether wing wear can account for mortality in foraging bumble bees. 3. Workers in eight wild-foraging colonies of bumble bee (Bombus melanopygus Nylander) were divided into two treatment groups: clipped (the outer margin of each forewing trimmed, reducing wing surface area by an average of 18%) and unclipped controls. The mortality and behaviour of foraging individuals was assessed with colony watches and night censuses. 4. Treatment did not detectably affect the proportion of foraging bees, the lengths of foraging or within-nest bouts of foragers, or pollen load sizes, but wing-clipping did cause bees with the greatest amounts of initial wing wear to stop foraging. 5. Mortality was positively related to natural wing wear among unclipped bees. In addition, relative to control foragers, foragers with clipped wing margins experienced significantly reduced life expectancies. 6. These results support the hypothesis that wing wear is a proximate factor responsible for an increase in mortality in older workers. The wing-wear hypothesis therefore provides one functional reason for foragers to adopt a currency that maximizes the ratio of net benefit to cost (i.e. 'efficiency').

Developmental and environmental sources of pheromone variation inColias eurytheme butterflies

Body size, age, ambient temperature, wing wear, and flight activity were investigated as possible sources of variation in the quantities and relative proportions of the three chemical components [n-heptacosane (C27), 13-methylheptacosane (13MH), andn-nonacosane (C29)] of the male courtship pheromone ofColias eurytheme butterflies. Size of the male has very little influence on the amount of any of the pheromone components present on the wings. Most of the deposition of all three components onto the surface of the hindwing occurs between 3 and 9 hr after emergence from the pupa. 13MH is deposited more rapidly than C27 and C29, and C27 more rapidly than C29. After the first 12 hr posteclosion, the pheromone phenotype of an individual male remains relatively constant through at least 96 hr of age. Experiments showed that none of the three chemicals volatilize to any appreciable extent at temperatures likely to be experienced in the field. The pheromones of actively searching and courting males did not differ from those of less-active feeding and resting males, suggesting that volatilization induced by flight activity is not an important source of pheromone variation. Loss of scales with age does seem to affect pheromone phenotype, but not in a readily interpretable way. Although the quantity of 13MH was lower in worn males than in fresh, C27 was higher.

Male Age, Copulation Duration and Insemination Success in Mystacides azurea (Leptoceridae, Trichoptera)

AbstractTime in copula in the swarming caddis fly Mystacides azurea L. (Trichoptera: Leptoceridae) ranged from 0.33 to 44.5 min. It increased with male age (wing wear) and male dry weight, but was independent of male and female size (forewing length), female wing wear and number of eggs in the females. Older males failed to transfer sperm during copulation more frequently than did younger ones. It is suggested that females benefit by interrupting prolonged copulations if sperm is not transferred rapidly, since being in copula might increase the risk of predation. Alternatively, young and old males follow different mating tactics; old males have a lower chance to acquire new mates and they do better by monopolizing a female, once they get one, by prolonging the copulation.

Age‐associated male mating success in three swarming caddis fly species (Trichoptera: Leptoceridae)

Abstract. 1. In the three caddis fly species, Athripsodes albifrons (L.), A. cinereus (Curtis) and Mystacides azurea (L.) (Leptoceridae; Trichoptera), males swarm above the water surface of lakes or rivers. Receptive females fly to swarms and are chased and/or courted by males. After one of the swarming males has grasped an approaching female, the pair flies in tandem to the shore where they copulate.2. In males, wing wear indices were negatively correlated with the ratio of fat/dry weight. In the only species in which comparisons were possible between newly emerged and swarming males (M. azurea), the former had significantly lower indices. Unmated females on average had lower wing wear indices than spent females. These facts suggest that wing wear reflects relative age.3. The tandem males had significantly less wing wear than those in swarms, and are probably therefore younger. Age is therefore likely to be significant in relation to mating success.4. Among males of the same relative age, tandem males had higher fat ratio than swarming ones, indicating that male mating success was also influenced by traits other than age. It is suggested that the shortest possible duration of the period of adult prematurity is adaptive, especially in insects with marginal adult food intake.

Population dynamics of Luehdorfia japonica Leech (Lepidoptera: Papilionidae)

Summary An adult population of a papilionid butterfly, Luehdorfia japonicaLeech, was studied by marking, release and recapture procedures in a hilly region in the suburbs of Kanazawa City, Japan. Age of butterflies was estimated from the wing wear conditions, rated as winage categories 0 to 6. Jolly (1965) andSeber's (1973) method was applied to the marking‐recapture results for estimating the population parameters (sampling ratio, population size and survival rate). Sampling ratio of males was consistently higher (around 50%) than that of females. Newly emerged females were especially inactive, so that few of them were captured. From day 6.5 to day 10.0 they began to oviposit and became more active and more catchable. An approximate sex ratio of 1∶1 was confirmed from the specimens collected in the field and by rearing experiments. Daily survival rate was about 0.75–0.80 and mean longevity was about 4 days for both sexes. The maximum longevity observed was 17 days, for males and 21 days for females. Dispersal by both sexes of the butterfly was more than 1 km.

Epigamic selection by males as evidenced by courtship partner preferences in the checkered white butterfly ( Pieris protodice)

Free-flying males of the checkered white butterfly, Pieris protodice, were presented with tethered females that varied with respect to both size (as measured by forewing length) and age (as measured by wing wear). Because males make a substantial investment in their offspring through nutrients passed to the female during copulation, they were expected to court young and large females for longer times than older and smaller females, and they did so. Additional experiments further suggest that size discriminations are made on the basis of apparent wing area and age discriminations are made on the basis of an age-related increase in ultraviolet reflectance that occurs in females. The discussion examines the adaptive value of these discriminations.

A population study in Jamaica on adult Sceliphron assimile (Dahlbom) (Hymenoptera: Sphecidae)

Abstract. A mark–recapture study on the sphecid wasp Sceliphron assimile (Dahlbohm), analysed by Jolly's stochastic method (1965), was made from 3 December 1974 to 22 February 1975 at Green Bay, St Catherine, Jamaica. Population levels in an 18.2 ha study area fluctuated about a mean of 281 for males, 259 for total females and 87 for reproducing females, while the probable carrying‐capacity for these reproductives was about 104. Mean estimated daily survival rates were 0.903 for males, 0.924 for total females and 0.945 for reproducing females. For the first two categories these rates decreased (p < 0.02) during the study, probably reflecting increasing emigration. Reproducing females probably do not emigrate and their survival did not significantly decrease. Minimum age was linearly related to wing wear (r=+0.69, P < 0.001) and the latter associated with the progressive maturation and ageing of the ovaries. All surviving females become parous by middle age. The mean rate of fecundity in the field was dependent on female age and was reduced during prolonged drought. Curves of total achieved fecundity appropriate to realistic survival rates give 4.2–16.8 eggs/female. The Jamaican mean was 9.6 ± 2.3 and that for Green Bay 8.6. The proportion of females in the Green Bay population was 0.48 ± 0.03 while 0.55 was expected at emergence. A cyclic budget is used to estimate immigration and emigration, and these were important causes of population change. For Jamaica, only an estimated 28% of females survived to nest.

Age structure of populations of Culex annulirostris (Diptera: Culicidae) at Kowanyama and Charleville, Queensland.

The separation of nulliparous from parous Culex annulirostris using ovarian tracheation proved quick and reliable. Determination of physiological age, based on the number of ovariolar dilalations, proved slow but workable although some reservations remain regarding its validity. Abdominal pigmentation (similar to that seen in biting midges of the genus Culicoides ), ovary color and consistency. body and wing wear, integumental color, presence of a meconium and presence of parasitic mites were generally of greater use than ovary size as indicators of parity. The physiological age of blood-seeking Cx. annulirostris , collected at Kowanyama (1540 specimens) and Charleville (1553) between 1974 and 1976, was determined by ovarian tracheation and ovariolar dilatation methods. Despite different climates, the seasonal age structures were similar at both localities, At Kowanyama and Charleville, 18.2% and 12,4%, respectively. were old enough to be capable of transmitting Murray Valley encephalitis virus. Gonactive pars and nullipars were collected throughout the year at both localities despite low winter temperatures at Charleville. The moderate longevity of Cx. annulirostris at Kowanyama (mean daily survival rate ± 1 standard deviation 72.1 + 10.1%) and Charleville (73.8 ± 11.7p) suggests that abundance may be a key factor contributing to the high vector potential of this species.