Dispersal pattern of the sand fly Lutzomyia neivai (Diptera: Psychodidae) in a cutaneous leishmaniasis endemic rural area in Southeastern Brazil

The dispersal pattern of the sand fly Lutzomyia neivai was studied through mark-release-recapture experiments in an American cutaneous leishmaniasis endemic rural area in Southeastern Brazil. Over 6500 specimens were marked with fluorescent powder and released in forest edge and peridomicile habitats from August to November 1999, February and April 2000. Recapture attempts were made using Shannon and CDC traps up to eight successive nights after releases. A total of 493 (7.58%) specimens were recaptured. The number of recaptured males and females of L. neivai in CDC traps was not affected by the distance between the trap and the release points. Approximately 90% of males and females recaptured in CDC traps were caught up to 70 m from the release points. The maximum female flight range recorded was 128 m. The average flight range per day was less than 60 m for males and females. Of the flies released in forest edge, approximately 16% of the recaptured females were caught in Shannon traps in the peridomicile habitat. The results indicate that the movements of L. neivai are spatially focal and the possibility of dispersion from forest to peridomicile habitat may be an important way of contracting leishmaniasis in dwellings.     

Non-breeding behaviour of Magenta Petrels Pterodroma magentae at Chatham Island, New Zealand

Magenta Petrels Pterodroma magentae were caught at light-attraction stations on southwest Chatham Island, New Zealand, and most were fitted with transmitters. Of 52 captured since 1993, 71% were males, and all 36 tracked adequately proved to be non-breeders in the breeding season of capture. Our data indicated no sex bias in their probability of being captured at lights. Males provided 86% of trackings, and 87% of trackings of birds flying over the breeding area were males. Males landed 118 times; females 13 times. Only males were found on the ground, by night and day, apparently unassociated with burrows (three with and ten without transmitters), but subsequently digging burrows ( n  = 8). Of 19 birds banded as fledglings up to 2000, males were first recaptured nearing 4 years old (at lights and on the ground) and a female nearing 6 years old (in burrow). Among 37 fledglings, the sex ratio was even. Nine tracked males occupied burrows, as did two females, but the latter were older recaptures (10+ and 25+ years old). It appears that only males claimed existing, or dug new, burrows. They then attracted a mate to the burrow by means unknown, but from among females frequenting an inshore courtship area near the colony, or occasionally flying over the colony, at night. Females established in burrows, but then losing their mate, were able to re-mate there, by calling from near the burrow or by attracting a mate in flight or from the postulated inshore courtship area. Both sexes sometimes took years to pair or re-mate, possibly reflecting the dearth of available mates.     

Adult survival and numbers in a coastal breeding population of Redshank Tringa totanus in northwest England

The results of a long-term capture-mark-recapture ringing programme carried out on a coastal population of breeding Redshanks Tringa totanus between 1974 and 1988 are presented.
Both sexes were equally likely to be recaptured in subsequent years, as were birds captured for the first time compared with those that had been captured previously. Older birds were more frequently recaptured than were young birds. There was no significant difference in male and female adult survival rates, with a mean of 72% of females and 75% of males surviving each year.
The breeding population fluctuated annually with estimated breeding densities of 122–285 pairs per km². Variation in breeding numbers (males), but not survival, was partially attributable to winter air temperature.     

Influence of attractants on behavior of screwworms (Diptera: Calliphoridae) in a tropical wet forest in Costa Rica.

In a mark-release-recapture study, sheep wounds and rotted liver were used as attractants to study movements of the screwworm fly, Cochliomyia hominivorax (Coquerel), in a Costa Rican tropical wet forest in the wet season. When sites were monitored for less than 1 h, liver attracted between 3 and 12.2 times more flies of both sexes than did wounds, but proportionately fewer gravid and parous females. Only 24.6% of females marked at liver sites were recaptured; seldom (3.1%) did they visit sheep wounds. Females originally marked at sheep wounds remained at the study site longer, visited both sheep and liver sites, and greater than 50% were recaptured. Some females were observed for 16 d and one laid four clutches of eggs. Only 8% of the marked males were recaptured and none was recaptured less than 2 d later. Only a small proportion of the adult screwworms at a locality visited wounds on sentinel sheep; the majority of the adults were transient.     

Foraging and habitat use by Nycteris grandis (Chiroptera: Nycteridae) in Zimbabwe

This study describes the foraging strategies, foraging areas, and roosts used by four female radio-tagged Nycteris grandis along the Zambezi River in Mana Pools National Park in Zimbabwe. The bats exhibited two foraging strategies, sometimes hunting from perches, other times flying continuously close to the ground. Some individuals used one strategy more than the other. During the study, the bats fed mainly on frogs, selecting only Ptychadena anchietae ; they also took crickets, moths and cicadas. Each bat usually consumed two frogs each night and patterns of occupation of feeding perches suggest that their foraging efficiency was between 21 and 36%. The marked bats roosted in an old water tower or in a hollow Acacia albida. Four of five marked females were nursing young during this study.     

The relationship between thePgi locus and the ability to fly at low temperatures in the monarch butterflyDanaus plexippus

Differences in genetic structure of samples of monarch butterflies caught at different times of day have been reported previously. This paper compares differences in allele and heterozygote frequencies at thePgi locus between animals flying early and those flying late in outdoor flight cages and between animals able and animals unable to fly at a constant low temperature. There were consistent effects across a number of tests and in comparisons with field data, especially in males. Animals with the Mallele were more likely to be able to fly at low temperatures, to become active early in outdoor flight cages, and to be caught early in the field. Also, differences were observed between males and females in the effect of allele on flight activity.     

Longevity and survival of female pipistrelle bats (Pipistrellus pipistrellus) on the Vale of York, England

Female pipistrelle bats ( Pipistrellus pipistrellus Schreber) form large nursery colonies in summer. Between 1977 and 1984, around York in the north of England, 1328 pipistrelle bats were ringed. Ninety adult females were ringed in 1977, and from capture, release and recapture data life tables for an unaged female cohort were constructed. Age-specific survival rate for adult females on the Vale of York was 0–64 per year. Three bats from the original 1977 cohort were recaptured in 1984 and are likely to have been at least eight years old. Juvenile female pipistrelles appear to survive less well than adults.     

Reproductive success, mortality and sexual size dimorphism in the adder, Vipera berus

From 1981 to 1986 an isolated adder population was studied in the extreme south of Sweden. During this period 48 adult males and 44 adult females were marked. Male adders did not grow as large as the females. Large males had a significantly higher annual mating success and were engaged in more combats than smaller males. The mean length of recaptured males was significantly lower than that of those not recaptured, indicating a higher motality of larger males. Females brood size was positively correlated with body size. In females there was no difference in mean length of recaptured vs not recaptured individuals. The adder is one of the few snake species with male combat where males are smaller than females. I suggest that this is due to stronger selective advantages for large body size in females than in males.     

Monitoring codling moth (Lepidoptera: Tortricidae) with passive interception traps in sex pheromone-treated apple orchards

Male and female codling moth, Cydia pomonella (L.), were monitored with passive interception traps (PI-traps) in apple orchards treated with sex pheromone dispensers. The proportion of mated females recaptured by PI-traps was significantly higher than the proportion released after the release of both sexes into a codling moth-infested orchard. However, no significant difference occurred between the proportion of mated females recaptured and released when only females were released into uninfested orchards. Replicated nine-tree apple plots situated either on the edge or in the center ofpheromone-treated apple orchards were monitored with PI-traps during first moth flight in 1995 and during both flights in 1996. Moths caught on PI-traps were predominately males. The first male moths were captured 7-10 d before females during the first flight in both years. Initial capture of virgin and mated females on PI-traps coincided in 1995. Mated females were captured 14 d after the first virgin females in 1996. The mean proportion of females that were mated ranged from 32 to 55% during the first flight and 85 to 92% during the second flight. Moth catch and fruit injury were significantly higher in the edge versus the center plots. The numbers of total and female moths caught with PI-traps were significantly correlated with fruit injury for each generation. The percentage of female moths caught on PI-traps that were mated was 32% lower and the mean oocyte load of all females was 42% higher in a pheromone-treated apple orchard than in the untreated crabapple grove monitored during May and June 1997.     

Seasonal variation in age,sex, and reproductive status of Mexican free-tailed bats

In North America, Mexican free-tailed bats (Tadarida brasiliensis mexicana) consume vast numbers of insects contributing to the economic well-being of society. Mexican free-tailed bats have declined due to historic guano mining, roost destruction, and bioaccumulation of organochlorine pesticides. Long-distance migrations and dense congregations at roosts exacerbate these declines. Wind energy development further threatens bat communities worldwide and presents emerging challenges to bat conservation. Effective mitigation of bat mortality at wind energy facilities requires baseline data on the biology of affected populations. We collected data on age, sex, and reproductive condition of Mexican free-tailed bats at a cave roost in eastern Nevada located 6 km from a 152-MW industrial wind energy facility. Over 5 years, we captured 46,353 Mexican free-tailed bats. Although just over half of the caught individuals were nonreproductive adult males (53.6%), 826 pregnant, 892 lactating, 10,101 post-lactating, and 4327 nonreproductive adult females were captured. Juveniles comprised 11.5% of captures. Female reproductive phenology was delayed relative to conspecific roosts at lower latitudes, likely due to cooler temperatures. Roost use by reproductive females and juvenile bats demonstrates this site is a maternity roost, with significant ecological and conservation value. To our knowledge, no other industrial scale wind energy facilities exist in such proximity to a heavily used bat roost in North America. Given the susceptibility of Mexican free-tailed bats to wind turbine mortality and the proximity of this roost to a wind energy facility, these data provide a foundation from which differential impacts on demographic groups can be assessed.     

Ectoparasite Raymondia lobulata infestation in relation to the reproductive cycle of its host--the greater false vampire bat Megaderma lyra

To study variation of infestations by the bat fly Raymondia lobulata (Diptera: Streblidae) on the greater false vampire bat Megaderma lyra (Chiroptera: Megadermatidae), we captured individual bats at their day roost in the south of India and recorded their rate of infestation continuously for a year. All examined bats (n = 72 individuals, 202 captures) were infested with parasites (n = 3,008). However, the recorded intensity of infestation (range 1-33) was gender-related and statistically higher in females than in males (F(1, 200) = 304.45, P < 0.001). Furthermore, pregnant and lactating females had greater parasite loads than non-reproductive females and males (F(1, 63) = 23.34, P < 0.001 and F(1, 37) = 78.07, P < 0.001, respectively). No significant differences were observed between males either during mating and non-mating periods or breeding and non-breeding seasons. Analysis of the relationship between parasite infestation and the reproductive status of bats revealed that pregnant and lactating females with pups were more vulnerable hosts for parasites. Our results also suggest a well-developed coevolutionary strategy for synchronized reproduction within the host-parasite relationship and add to our understanding of how host sex and reproductive status shape the dynamics of parasitism.     

Some factors affecting the efficiency of water-traps for capturing cabbage root flies

Several factors influencing the efficiency of water-traps in capturing cabbage root flies were studied at Wellesbourne in 1971 and 1972. In both the laboratory and field, approximately twice as many flies were caught in fluorescent as in non-fluorescent yellow traps. Depending upon trap density, addition of a source of the attractant allylisothiocyanate (ANCS) increased the numbers of females captured by approximately twofold in fluorescent traps and from two- to sevenfold in non-fluorescent traps. Traps were equally efficient irrespective of whether the ANCS was renewed every 2, 3, 4 or 5 days. On the first day of trapping, the number of flies caught per unit area was linearly related to the square root of the number of traps in that area. On the following days the rate was probably in equilibrium with the combined effect of immigration and the rate of development of responsive flies in the trapping zone. Most males were caught 30 cm above the soil surface and most females at soil level. Traps 120 cm above the soil surface caught few flies. Populations of marked flies were released into large field cages containing both a section of hedgerow and a plot of cauliflowers. Even after a week, only 81 % of the males and 55 % of the females had been recaptured from the most responsive of these captive populations. Furthermore, only 30 % of females were recaptured when they were more than 8 days old, the age at which most probably enter the new host-crop.     

The effect of ultrasound on the attractiveness of acoustic mating signals

Abstract. Previous laboratory studies ( Nolen & Hoy 1986b ) have shown that the phonotactic responses of flying crickets are influenced by the relative intensities of attractive (mating signal) and repulsive (predator) stimuli. At the functional level, these results suggest that predator cues (ultrasound) can change the attractiveness of a calling song. Using extracellular recordings from cervical connectives it was shown that, like other field crickets, Gryllus rubens (south-eastern field cricket) is sensitive to ultrasound. This ultrasonic sensitivity has probably evolved in response to predation pressure from echolocating bats. Using acoustic playback under field conditions, it was tested whether the relative attractiveness of two male calling songs was influenced by the simultaneous broadcast of ultrasound. A simulated male calling song of G. rubens was broadcast at two different intensities (109 and 103 dB) from two sound traps that caught flying crickets attracted to the songs. Simulated bat ultrasound was broadcast simultaneously with the high-intensity calling song (109 dB) and the relative catch in each of the two traps was measured. The intensity of the ultrasound was varied on different nights. The relative attractiveness of the high-intensity sound trap decreased significantly as the intensity of the ultrasound broadcast with it was increased. For the lowest of the ultrasound broadcast levels, the relative attractiveness did not differ from that expected for two calling songs broadcast without ultrasound. Thus, increased levels of simulated predation risk decreased the attractiveness of the calling song associated with it. These are the first field experiments to show that predation risk in the form of simulated bat ultrasound influences the phonotactic behaviour of flying crickets.     

Free-Ranging Little Brown Myotis (Myotis lucifugus) Heal from Wing Damage Associated with White-Nose Syndrome

White-nose syndrome (WNS) is having an unprecedented impact on hibernating bat populations in the eastern United States. While most studies have focused on widespread mortality observed at winter hibernacula, few have examined the consequences of wing damage that has been observed among those bats that survive hibernation. Given that WNS-related wing damage may lead to life-threatening changes in wing function, we tested the hypothesis that reduced abundance of free-ranging little brown myotis (Myotis lucifugus) with severe wing damage as the summer progresses is due to healing of wing tissue. Photographs of captured and recaptured adult females were examined for wing damage and healing rates were calculated for each category of wing damage index (WDI = 0–3). We found that free-ranging bats with severe wing damage were able to heal to a lower WDI score within 2 weeks. Bats with the most severe wing damage had faster healing rates than did individuals with less damage. We also found a significant relationship between body condition and WDI for adult females captured in the early weeks of the active season. Our results support the hypothesis that some bats can heal from severe wing damage during the active season, and thus may not experience increased mortality associated with reduced functions of wings. We urge researchers and wildlife managers to use caution when interpreting data on WDI to assess the impact of WNS on bat populations, especially during the later months of the active season.     

Capture of Mediterranean fruit flies (Diptera: Tephritidae) in dry traps baited with a food-based attractant and Jackson traps baited with trimedlure during sterile male release in Guatemala

Captures of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), in Jackson traps baited with trimedlure were compared with captures in cylindrical open-bottom dry traps baited with a food-based synthetic attractant (ammonium acetate, putrescine, and trimethylamine). Tests were conducted in Guatemala during a sterile male release program in an area where wild flies were present in low numbers. More wild and sterile females were captured in food-based traps, and more wild and sterile males were captured in trimedlure traps. The food-based traps captured almost twice as many total (male plus female) wild flies as the trimedlure traps, but the difference was not significant. Females made up approximately 60% of the wild flies caught in the food-based attractant traps; the trimedlure traps caught no females. The ratio of capture of males in trimedlure traps to food-based traps was 6.5:1 for sterile and 1.7:1 for wild flies. Because fewer sterile males are captured in the food-based traps, there is a reduction in the labor-intensive process of examining flies for sterility. The results indicate that traps baited with food-based attractants could be used in place of the Jackson/trimedlure traps for C. capitata sterile release programs because they can monitor distributions of sterile releases and detect wild fly populations effectively; both critical components of fruit fly eradication programs by using the sterile insect technique.     

The biology of the stoat (Mustela erminea) in the National Parks of New Zealand IV. Reproduction

Abstract

The gonads of 528 female and 821 male stoats were examined. The weights of ovaries and testes in adults peaked simultaneously in October, the season of births and of post-partum oestrus. Of 73 females, 78% had even numbers of nipples, mostly 8 or 10. The mean number of embryos in 13 pregnancies was 8.8 (6–13), and embryo weights ranged from 0.005 g to 2.9 g. Of 11 pregnant females, 8 contained fewer embryos than corpora lutea, and there was evidence of transuterine migration of blastocysts in 6. All but 2 of 451 females caught in December–July inclusive carried corpora lutea of delay. Few adult and no young females were found in oestrus in September–October, though adult males were fertile from August to February (no first-year males were fertile). There was some evidence that the breeding season started later at more southerly latitudes in both males and females. The mean number of corpora lutea per female was 9.7 (n = 439), and there was a significant inverse correlation between counts for the 2 ovaries of one individual. There was generally no significant variation in fecundity of females with age, body weight, or year. Of 11 females which were considered to have lost their litters, 10 were collected in beech (Nothofagus) forests. Four females and 9 males had abnormal gonads; the most severe abnormality was an ovarian teratoma of unknown pathology.     

Olive fruit fly (Diptera: Tephritidae) populations in relation to region, trap type, season, and availability of fruit

Olive fruit fly, Bactrocera oleae (Gmelin), was monitored with adult captures by season and trap type, and was related to fruit volume and nonharvested fruit to elucidate the occurrence of the newly introduced pest in California. The highest numbers of adults captured in ChamP traps in olive trees, Olea europaea, were in October in an inland valley location, and in September in a coastal location. Comparisons of trap types showed that the number of olive fruit fly adults captured in Pherocon AM traps in a commercial orchard was significantly greater than in ChamP traps. A significantly greater number of females were captured in Pherocon AM traps with bait packets and pheromone lures than traps with pheromone lures alone, while a significantly greater number of adults and males were captured in traps with pheromone lures alone. Significantly more adults were captured in ChamP traps with bait packets and pheromone lures versus traps with bait packets alone. Fruit volume increased by four times from mid-June to mid-November. Olive fruit fly was found to oviposit on small olive fruit <1 cm3 shortly after fruit set, the maximum number of ovipositional sites per fruit occurred in October, and the greatest number of pupae and adults were reared from fruit collected in September and October. The highest numbers of pupae were collected from nonharvested fruit in March when high numbers of adults were captured in the same orchard.     

Signals for Survival in the Lives of Crickets

Two behavioral acts of undoubted survival value are predatoravoidance and mate choice. In field crickets both are mediatedby acoustic signals containing high frequency spectral energy.Nocturnally active bats use ultrasonic echolocation signalsto detect and locate their prey, which includes insects thatdisperse by flying at night. Many insects have developed ultrasoundavoidance behaviors in flight, in order to elude bats. In crickets,an auditory interneuron that is excited by ultrasound has beenidentified and shown to initiate the avoidance behavior; itis a putative bat-detector cell. Male field crickets produceacoustic signals during their courtship (females are mute).Courtship song appears to facilitate mating success (copulation),for its absence in courtship diminishes the likelihood of copulation.The possible role of the bat-detector neuron in courtship behavioris considered because it is activated by courtship signals aswell as bat-like ultrasound. The role of behavioral contextshapes the participation of neurons in the neural networks thatunderlie a given behavior.     

Intraspecific variation in body size and sexual size dimorphism,and a test of Rensch's rule in bats

The magnitude and direction of sexual size dimorphism (SSD) may vary considerably within and among taxa, and the primary causes of such variation have not been thoroughly elucidated. For example, the effect of abiotic factors is frequently attributed to explain intra‐ and interspecific variation in SSD. Rensch's rule, which states that males vary more in size than females when body size increases, has rarely been tested in bats. Therefore, whether bats follow Rensch's rule remains unclear, particularly when females are larger than males. We investigated whether four bat species presented SSD, as well as whether their body sizes varied within each sex across localities, testing the hypothesis that intraspecific SSD varies substantially depending of sampling localities. We finally examined whether bats followed Rensch's rule by simultaneously using intraspecific and interspecific approaches. Although SSD was not observed for most bat species within each locality, the females of three of the four captured species exhibited differences in body size between particular localities. Usually the females varied more in size than did males across localities, mostly exhibiting a female‐biased SSD. Significant differences in SSD were observed (i.e. mean values of the sexual dimorphism index), even though Rensch's rule was not followed.     

A population study of bats of the Genus Plecotus

In November 1960, bat colonies were found in the roof of the research station, and an ecological study began of the largest, a Plecotus colony. That colony was at first thought to consist solely of P. auritus but, in 1964, the presence of P. austriacus was confirmed, and several of the latter had been ringed early in 1961. Because of this, it has been necessary to present, here, the combined results for the two species. Population studies revealed that the colony size was constant and consisted of 36 bats of which 23 were females. Overall 38% were males but, of the juveniles, 46% were males. The survival rate for the colony as a whole was 0.750, but the mean life expectation for females was 4.2 years and for males 3.7 years. The life-span was thought to be in excess of 16 years. Initial capture rate of 0.715 remained constant throughout the five-year period, while the recapture rate fell by a factor of 0.30. This was attributed to sampling disturbance and not due to ringing. Mating was found to occur equally in spring and autumn. Males became mature in their first year and females in their second. The mean spring and autumn weights for mature males were generally 1.5g less than the corresponding mature female weights, and juvenilesare approximately 1.0 g less than these. Climatic effects on the bats were demonstrated with particular reference to wind velocity. This work is beingcontinued.