Pre- and post-maturation survival in adults of the damselfly Pyrrhosoma nymphula (Zygoptera: Coenagrionidae)

The technique of mark-release-recapture was used to study survival before and after sexual maturity in adults of the damselfly Pyrrhosoma nymphula (Sulzer). Fewer females were recaptured upon return to water to breed despite no differences in dispersal or daily survival rate between the sexes over the immature period. Because females took longer to mature than males, their poorer recapture rate was attributed to greater overall mortality during their longer maturation phase. Survivorship curves for tenerals marked at emergence suggested that overall survival of immature adults was similar to, if not better than, that of mature adults. The reasons for this are discussed.
Jolly's model was used to estimate daily survival rates for mature adults. The assumptions of the model were tested rigorously. Estimates for females were statistically less reliable than those for males. Mean reproductive spans for males and females were 6.8 and 6.6 days, respectively, giving mean total adult lifespans of 19.4 days and 21.6 days for individuals surviving the maturation period.
Because neither sex visited the breeding site every day, sampling exclusively at water resulted in underestimation of mean reproductive spans for both sexes. Female reproductive spans were underestimated to a greater extent; because females remain away from water longer between visits, there is a greater chance that they will die before being recaptured.
Mean reproductive spans were also underestimated when only a sub-section of the habitat was sampled. Females were significantly more mobile than males and this increased the likelihood that they would move out of the study area, resulting in more severe underestimation. The importance of obtaining accurate estimates of mature lifespan for females is discussed.     

Biology of Triatoma pallidipennis stal 1945 (Hemiptera: Reduviidae:Triatominae) under laboratory conditions

Aspects related to hatching, life time, mortality, feeding behaviour and fecundity for each stage of Triatoma pallidipennis life-cycle were evaluated. The hatching rate observed for 200 eggs was 60% and the average time of hatching was 18 days. Eighty nymphs (N) (40%) completed the cycle and the average time from NI to adult was 168. 7+/-11.7days. The average span in days for each stage was 18.0 for NI, 18.5 for NII, 30.0 for NIII, 35.7 for NIV and 50.1 for NV. The number of bloodmeals at each nymphal stage varied from 1 to 5. The mortality rate was 9.17 for NI, 5.5 for NII, 6.8 for NIII 4.17 for NIV and 13.04 for NV nymphs. The average number of eggs laid per female in a 9-month period was 498.6. The survival rates of adults were 357+/-217.9 and 262.53+/-167.7 for males and females respectively.     

Dynamics of Pneumonia in a Bighorn Sheep Metapopulation

Abstract: We investigated the dynamics of 8 populations of a bighorn sheep (Ovis canadensis) metapopulation in Hells Canyon, USA from 1997 to 2003. Pneumonia was the most common cause (43%) of adult mortality and the primary factor limiting population growth. Cougar (Puma concolor) predation was the second most-frequent source (27%) of adult mortality but did not reduce the rate of population growth significantly. Most pneumonia-caused mortality occurred in fall and early winter and most cougar predation occurred in late winter and early spring. Average annual survival of adult males (0.84) was lower than females (0.91). Pneumonia was the most common known cause of lamb mortality (86%), and pneumonia-related mortality was detected whenever summer lamb survival was <50%. Pneumonia-caused mortality rates in lambs were high from 21 days to 91 days of age and peaked at 42 days to 70 days. Summer pneumonia epizootics in lambs were independent of pneumonia-caused mortality in adults. Pneumonia-caused mortality occurred at the population level and was not synchronized geographically or temporally among populations. Although catastrophic all-age pneumonia-epizootics have previously been described in bighorn sheep, we found that chronic, although sporadic, pneumonia-caused mortality in adults and lambs can also have important effects on the dynamics of bighorn sheep populations.     

Life table and biological studies of Harmonia axyridis Pallas (Col., Coccinellidae) reared on the grain moth eggs of Sitotroga cerealella Olivier (Lep., Gelechiidae)

The developmental period of immature stages, survival per cent, longevity, fecundity and life table parameters of Harmonia axyridis by feeding on fresh and frozen grain moth eggs (GME) of Sitotroga cerealella were studied under laboratory conditions. The effect of crowding adults on fecundity of females was also determined. The total developmental time from egg hatching to adult eclosion ranged from 18.89 ± 0.32 to 22.5 ± 0.21 days on fresh and frozen GME, respectively. Survival per cent from egg hatching to adult emergence differed significantly when the predator fed on the two diets of GME. Also, pupal and adult weights were affected by feeding on fresh and frozen GME. There were no significant differences in longevity of females, while there were significant variations in fecundity of females and longevity of males. The calculated values of T , DT , R_o , r_m , and e^rm were high by feeding on fresh GME. Morever, rates of survivorship ( Lx ), and maximum oviposition per female per day ( Mx ) were higher when the predator was reared on fresh than on frozen GME. Crowding conditions of predator adults affected the fecundity of females due to egg cannibalism by both males and females of the predator.     

Feeding and survival of the malaria vector Anopheles gambiae on plants growing in Kenya

The propensity of the malaria vector mosquito Anopheles gambiae Giles (Diptera: Culicidae) to ingest sugars from various plants, and subsequent survival rates, were assessed with laboratory-reared males and females offered eight species of plants commonly cultivated and/or growing wild in western Kenya. In cages (no-choice bioassay), mosquitoes given the opportunity to feed on castorbean (Ricinus communis L.) had the longest survival times (mean and median survival time of 6.99 +/- 0.23 and 5.67 +/- 0.17 days, respectively), comparable to mosquitoes given 6% glucose (mean and median survival time of 8.70 +/- 0.23 and 6.67 +/- 0.33 days, respectively). Survival rates of An. gambiae were low on the other plants, comparable to mosquitoes given only water. Three plants: sweet potato (Ipomoea batatas L.), wild sage (Lantana camara L.) and castorbean provided levels of sugar ingestion by both sexes of An. gambiae detectable using the cold anthrone method, showing a positive correlation between median survival and sugar consumption (Spearman rank correlation coefficient = 0.905, P < 0.0001). Equal numbers of males and females were released in an enclosed semi-field screenhouse system containing a range of local plants, but no host for blood, and allowed to feed ad libitum: 6.7 +/- 0.5% (11/64) of those recaptured were found to contain detectable fructose (all females). Common plants are clearly a viable source of nutrition for adult female An. gambiae, as well as males, and may constitute and important resource for this important malaria vector.     

Developmental times and life tables for shore flies, Scatella tenuicosta (Diptera: Ephydridae), at three temperatures

Development times and survivorship of immature shore flies and longevity and reproduction of adult shore flies, Scatella tenuicosta Collin, reared on algae-infested filter paper, were studied at three temperatures (constant 20, 26, and 28.5 degrees C) through life table analysis. The development time for each individual life stage and the total time from egg to adult decreased with increasing temperature. Duration of the third (ultimate) larval instar ranged from 3.3 +/- 0.09 d at 20 degrees C to 1.4 +/- 0.04 d at 28.5 degrees C and was 1.7-1.9 times longer than the approximately equal first and second instars. Development of male and female shore flies from egg to adult needed an average of 14.5 +/- 0.13, 8.2 +/- 0.05, and 7.0 +/- 0.04 d at 20, 26, and 28.5 degrees C, respectively, and needed an estimated 154.4 +/- 1.2 thermal units (degree days). At these respective temperatures, adult females lived 21.8 +/- 2.2, 19.9 +/- 2.4, and 15.0 +/- 1.4 d and produced 379 +/- 62, 710 +/- 119, and 477 +/- 83 eggs during oviposition periods of 14.3 +/- 2.1, 15.0 +/- 2.2, and 10.8 +/- 1.4 d; daily lifetime egg production averaged 16.3 +/- 2.3, 33.5 +/- 3.8, and 29.7 +/- 3.5. Developmental stage-specific mortality was relatively low for all life stages at all temperatures, with maximum percent mortalities of 5.7% occurring in both the egg stage and in the third instar. The highest net reproductive rate (R(o)) was obtained for insects reared at 26 degrees C and was 329.6. The intrinsic rate of natural increase (r(m)) was highest at 28.5 degrees C and was 0.430. Generation time and doubling time of the population were shortest at 28.5 degrees C and were 12.4 and 1.6 d, respectively. Results suggested that 26 degrees C was near optimum for reproduction.     

Population structure of the rare damselfly,Ischnura gemina (Kennedy) (Odonata: Coenagrionidae)

Summary The population structure of the endemic San Francisco Bay Area damselfly, Ischnura gemina, is examined using mark-recapture methods. Average daily movements, sex ratios, population size, maturation times, survivorship, and dispersion patterns, were recorded and calculated from two small (each less than one hectare) sites 150 m apart in Glen Canyon, San Francisco. Of 563 adults marked over 36 days, 412 (73%) were recaptured at least once. Average daily movements for males and females were less than 6 m, suggesting local movements. However, directional movements of 150 m were observed from one site to the other, indicating dispersal potential. One of the populations was a satellite composed entirely, of emigrating individuals from the other site; no larvae or teneral adults were found at the satellite area. Males were more aggregated than females at both sites. Both sexes were highly clumped at one site but were nearly randomly dispersed at the other site. Total population size for both sexes tended to be constant throughout the sampling period, at about 250. Adult population estimates showed more males were present than, females, but larval counts at one site indicated only a slight excess of males. Average life span estimates ranged from 6.5 days (females) to 23.3 days (males). One male lived at least 36 days. Maturation time for males was about 5–7 days, 7–10 days for females. A long life span and long flight season (March to November) are probably adaptations to the foggy San Francisco climate. All populations of I. gemina located to date are small, possibly originating from founders from nearby demes, and may be subject to different selection pressures. The dispersal potential of I. gemina may increase its chance of survival should small urban demes be threatened with destruction.     

Growth and mortality in juvenile European wild rabbits (Oryctolagus cuniclus)

Factors influencing the growth and mortality patterns of young were examined in a small population of European wild rabbits. Juveniles were trapped and tagged for individual identification soon after their emergence from underground nests. Age was estimated from weight on first capture and survivorship determined from the last date individuals were observed. Differences in growth rates of young born throughout the season and between the three years of the study were related to population density. Maternal social status had no significant effect on post-emergence growth rates of kittens, or on offspring survival. Young born in females' first litters of the season, in March, had significantly lower mortality than subsequent litters. Cats and stoats were regularly observed on the study site and are likely to have been major agents of juvenile mortality. There was no difference in the growth rates of the sexes, and correspondingly non-breeding adult males and females were of similar body weight. From their first days above ground juvenile males suffered significantly higher mortality than females. Differential mortality may be linked to previously reported sex differences in behaviour if the greater activity of young males made them more vulnerable to predation or attack by neighbouring territorial conspecifics.     

Body size as an indicator of parasitoid quality in male and female Anagyrus kamali (Hymenoptera: Encyrtidae)

The parasitoid Anagyrus kamali Moursi was recently introduced into the Caribbean as a biological control agent against the hibiscus mealybug, Maconellicoccus hirsutus Green. In the laboratory, parasitoid size, as measured by left hind tibia length, was positively correlated with several indicators of the parasitoid's fitness: longevity, mating preference, fecundity, reproductive longevity, progeny emergence and sex-ratio. When fed ad libidum with honey drops, large male parasitoids lived significantly longer (29.1 +/- 6.5 days) than small ones (18.4 +/- 5.7 days). Large females also lived significantly longer (35.4 +/- 10 days) than small females (27.9 +/- 9.6 days). Females showed no significant mating preference between large and small males. Lifetime fecundity was positively correlated with the size of adult females and ranged from 37 +/- 21 eggs for small females to 96 +/- 43 eggs for large ones. The reproductive longevity, daily oviposition rate, and number of progeny were also higher among large parasitoids. The sex ratio of progeny from small female parasitoids was higher (0.76 +/- 0.24) than that of large individuals (0.47 +/- 0.18).     

Sex Ratio and Sexual Size Dimorphism in a Toad-headed Lizard,Phrynocephalus guinanensis

Phrynocephalus guinanensis has sexual dimorphism in abdominal coloration, but its ontogenetic development of sexual size dimorphism(SSD) is unknown. Using mark-recapture data during four days each year from August from 2014 to 2016, we investigated the development of sex ratios, SSD, sex-specific survivorship and growth rates in a population of P. guinanensis. Our results indicated that the sex ratio of males to females was 1:2.8. Males had a lower survival rate(6%) than females(14%) across the age range from hatchling to adult, which supported the discovered female-biased sex ratio potentially associated with the low survival rate of males between hatchlings and juveniles. Male-biased SSD in tail length and head width existed in adults rather than in hatchling or juvenile lizards. The growth rates in body dimensions were undistinguishable between the sexes during the age from hatchling to juvenile, but the growth rate in head length from juvenile to adult was significantly larger in males than females. Average growth rate of all morphological measurements from hatchling to juvenile were larger compared with corresponding measurements from juvenile to adult, but only being significant in tail length, head width, abdomen length in females and snout-vent length in males. We provided a case study to strengthen our understanding of the important life history traits on how a viviparous lizard population can survive and develop their morphology in cold climates.     

Fitness consequences of alternative life histories in water striders,Aquarius remigis (Heteroptera: Gerridae)

Using field and laboratory observations and experiments over 3 years, I investigated whether reproductive trade-offs shape individual life histories in two natural populations of the water strider, Aquarius remigis, in which univoltine and bivoltine life cycles coexist. Both later eclosion dates and food shortages, even after adult eclosion, induced diapause in females, thus deferring reproduction to the following spring. Adult body size was positively affected by food availability during juvenile development. Higher food levels also increased the reproductive output of females, but not their longevity or oviposition period. When compared to spring breeders (univoltine life cycle), direct (summer) breeders (bivoltine life cycle) experienced reduced lifetime egg numbers and longevity, as well as reduced survivorship of their second-summer-generation offspring; these reproductive costs offset, at least in part, the advantage in non-decreasing populations of having two generations per year. Fecundity was correlated with body size, and among summer-generation females direct breeders were larger than non-breeders. The time remaining before the onset of winter and/or the time since adult eclosion augmented cumulative energy uptake, and consequently the lipid reserves and winter survival probability of non-breeding (diapausing) summer adults approaching hibernation. Overwintered spring reproductives died at faster rates than non-reproductive summer individuals despite greater food availability in spring, indicating a mortality cost of reproduction. Body length correlated with absolute and not with proportional lipid content but showed no consistent relationship with survivorship in the field. These results are in agreement with current theory on the evolution of insect voltinism patterns, and further indicate high degrees of life history flexibility (phenotypic plasticity) in the study populations in response to variable environmental factors (notably photoperiod and food availability). This may be related to their location in a geographic transition zone from uni- to bivoltine life cycles.     

Comparative survivorship and life history of painted greenling (Oxylebius pictus) in Puget Sound,Washington and Monterey Bay,California

Synopsis The painted greenling, Oxylebius pictus, a hexagrammid fish of shallow, northeastern Pacific rocky habitats was observed and collected near the center of its range at Monterey Bay, California, and near the northern limit of its distribution at Puget Sound. Life history characteristics were compared for breeding stocks from the two areas. Mean and maximum adult body sizes (lengths and wet weights) and longevities of both sexes are greater at Puget Sound. Also, both males and females reach sexual maturity at a smaller body length at Monterey. Age group 0 and I juveniles are twice as abundant as adults at Monterey but rare at Puget Sound. Monterey females have greater relative fecundities. Egg development rates are similar at equivalent temperatures; eggs are smaller, however, at Monterey, and thus embryos are smaller at hatching. Length increase is faster for Puget Sound juveniles; adult fish in the two areas grow in length at comparable rates, although weight per body length is consistently greater for Monterey fish. These findings reflect a poorer survivorship at Monterey, where natural predation on fertilized eggs and the mortality rates of adult males are greater.     

Sex ratio,survival, and recapture rate in a Cuban population of the damselfly <Emphasis Type="BoldItalic">Hypolestes trinitatis</Emphasis> (Odonata: Megapodagrionidae)

Male-biased sex ratios in adult odonate populations have been the subject of vigorous discussion between the students of this order of insects. The debate has centered on whether the observed male bias in many populations is real, perhaps due to unequal survival rates, or whether it is an artifact caused by differences in recapture probabilities. A mark–recapture study to assess the relative contribution of survivorship and recapture rates on male-biased sex ratio was performed in a Cuban population of the damselfly Hypolestes trinitatis. Maximum likelihood theory and Akaike information criterion were used for parameter estimation and model selection, respectively. Females in the sample were outnumbered two to one by males. Estimated recapture and survival rates were 0.188 (females) and 0.638 (males), and 0.933 (females) and 0.944 (males), respectively. Recapture rates only partially explained the bias since the population sex ratio estimated after correcting for differences in this parameter was male biased (1.5). The observed higher survival probabilities in males could have generated the male-biased population sex ratio. Therefore, we concluded that the observed male-biased population sex ratio in H. trinitatis is real.     

Biology of Triatoma flavida Neiva, 1911 (Hemiptera: Reduviidae) under laboratory conditions

The complete life cycle of Triatoma flavida, weekly fed on hens, was studied at 28+/-2 degrees C and 80+/-10% RH. Aspects related to hatching, life span, mortality and feeding behavior for each stage of its life cycle were evaluated. The hatching rate observed for 100 eggs was 93% with an average incubation period of 27.2 days. Sixty-two nymphs completed the cycle and the mean egg to adult development time was 230.4 days. Mean duration of 1st, 2nd, 3rd, 4th and 5th instar nymphs was 22.1, 25.3, 36.7, 49.7 and 69.4 days, respectively. The number of blood meals on each nymphal stage varied from 1 to 7. The mortality rate was 6.5% for NI, 23% for NIII and 7.5% for NV nymphs. Mean number of laid eggs per female was 283.1. Adult survival rates were 344.8 +/- 256.4 days for males and 285.3 +/- 201.8 days for females.     

Variation in life table characteristics among populations of Phlebotomus papatasi at different altitudes.

Baseline biological growth data were obtained under laboratory conditions for four local populations of the phlebotomine sand fly R papatasi (Scopoli, 1786) (Diptera: Psychodidae) in different eco-regions at altitudes between 368 and 1117 m in the Sanliurfa province of Turkey. The developmental time from egg to adult was found to be significantly different among the populations: 36 days for the AKL population (368 m), 43 days for the HHR population (488 m), 45 days for the HMD population (644 m), and 49 days for the ALT population (1117 m), respectively. Based on cohorts of adults in each population, horizontal life tables were constructed. The average longevity was determined to be in the range of 8.75 +/- 2.39 to 11.60 +/- 3.48 days for adult females, and it was found to be slightly longer for adult males. No significant difference was found in life expectancy at emergence, e(x) when x=1, between females and males in general (P>0.05) in all the populations. While significant differences could be demonstrated among populations for predictive parameters such as net reproductive rate, Ro, and generation time, Tc, no significant differences among the populations were found in terms of intrinsic rate of increase, r(m), finite rate of increase, lambda, birth (b) and death (d) rates (P>0.05). Populations that produced offspring earlier in life also produced more total female offspring, since Tc was negatively correlated with Ro among the populations (r = -0.686, 0.01相似文献   

Longevity and pheromone output in stored-product Bostrichidae

Information on longevity and on the effect of ageing on pheromone signalling in Bostrichidae infesting stored products is important because pheromones play a crucial role in mediating aggregation by the species in storages. The longevity of starved and unstarved Prostephanus truncatus (Horn) and Rhyzopertha dominica (Fabricius) were determined at 28+/-1 degrees C, 65+/-2% RH and L12:D12 cycle. Additionally, the effects of ageing on rate of pheromone emission were investigated in R. dominica by comparing emission rates of the aggregation pheromones Dominicalure-1 (DL1) and Dominicalure-2 (DL2) released by adult males ranging from 4, 8, 12, 24 and 48 weeks of age. Mean survival time of starved male and female P. truncatus was 8.6+/-0.6 and 9.1+/-0.4 days, respectively. Starved R. dominica males lived for 5.7+/-0.2 days, and females for 4.7+/-0.1 days. However, mean survival times were not significantly different for starved males vs. females of either species. Mean survival time of unstarved male and female P. truncatus was 27.5+/-2.0 and 18.0+/-3.3 weeks, respectively, and for unstarved male and female R. dominica was 26.1+/-2.8 and 16.7+/-2.9 weeks, respectively. Difference in mean survival times of unstarved males vs. females in both P. truncatus and R. dominica were significant. Between species, no significant difference was observed in mean survival time between unstarved males of P. truncatus or R. dominica, nor between females of both species. Rate of pheromone emission in R. dominica was higher when the insects were relatively young (4, 8 and 12 weeks old), but declined by almost 55% in treatments where the insect were at about 24 or 48 weeks old, suggesting that recruitment potential of R. dominica might reduce substantially as the insects age.     

Radiation biology and inherited sterility of light brown apple moth (Lepidoptera: Tortricidae): developing a sterile insect release program

The radiation biology of two geographically isolated populations of the light brown apple moth [Epiphyas postvittana (Walker)] was studied in Australia and New Zealand as an initiation of a SIT/F1 sterility program. Pharate and < or = 2 d pre-emergence pupae were exposed to increasing radiation doses up to a maximum dose of 300 Gy. Fertility and other life history parameters were measured in emerging adults (parental) and their progeny (F1-F3 adults). Parental fecundity was significantly affected by increasing irradiation dose in pharate pupae only. For both populations, parental egg fertility declined with increasing radiation. This was most pronounced for the irradiated parental females whose fertility declined at a higher rate than of irradiated males. At 250 Gy, females < or = 2 d preemergence pupae produced few larvae and no adults at F1. No larvae hatched from 250 Gy-irradiated female pharate pupae. At 300 Gy, males still had residual fertility of 2-5.5%, with pharate pupae being the more radio-sensitive. Radiation-induced deleterious inherited effects in offspring from irradiated males were expressed as increased developmental time in F1 larvae, a reduction in percent F1 female survival, decreased adult emergence and increased cumulative mortality over subsequent generations. Males irradiated at > or = 150 Gy produced few but highly sterile offspring at F1 and mortality was > 99% by F2 egg.     

Bioenergetics of age-related versus size-related reproductive tactics in female Viviparus georgianus

Individual Viviparus georgianus from a New York population are iteroparous, maturing in their second year. Ovoviviparous females have a maximum lifespan 1 year longer than that of males (4 + versus 3+ years), though individuals of both sexes can be reproductively active for three consecutive years. Embryophores are carried over winter and released each spring. Female survivorship is positively size related, as is incremental growth within any year. Reproductive effort is age related, increasing from 5.3% for modal 2-year females to 79.7% for modal 4-year females. Reproduction is size limited in 2-year females, no females below 16 mm shell length were found containing broods. The lack of observable survivorship penalties related to reproduction may result from reproductive females have greater biomass and hence greater survivorship. Spat size is positively correlated with female age irrespective of female size, though brood numbers increase with maternal size and growth rates. Caged experiments have shown spat born early to older females grow fastest. Data presented indicate that the young of older females have greater expected lifetime fecundity and fitness. In this population, 3-year females produce approximately 50.0% of each new cohort, with 2-year and 4-year females producing 21.0% and 26.0% respectively. Matrix models of the natural population and modified hypothetical populations emphasize the importance of survivorship and early reproduction in such stable, age-structured populations.     

Global climate patterns explain range-wide synchronicity in survival of a migratory seabird

To predict the impact of climate change over the whole species distribution range, comparison of adult survival variations over large spatial scale is of primary concern for long-lived species populations that are particularly susceptible to decline if adult survival is reduced. In this study, we estimated and compared adult survival rates between 1989 and 1997 of six populations of Cory's shearwater ( Calonectris diomedea ) spread across 4600 km using capture–recapture models. We showed that mean annual adult survival rates are different among populations along a longitudinal gradient and between sexes. Variation in adult survival is synchronized among populations, with three distinct groups: (1) both females and males of Corsica, Tremiti, and Selvagem (annual survival range 0.88–0.96); (2) both females and males of Frioul and females from Crete (0.82–0.92); and (3) both females and males of Malta and males from Crete (0.74–0.88). The total variation accounted for by the common pattern of variation is on average 71%, suggesting strong environmental forcing. At least 61% of the variation in survival is explained by the Southern Oscillation Index fluctuations. We suggested that Atlantic hurricanes and storms during La Niña years may increase adult mortality for Cory's shearwater during winter months. For long-lived seabird species, variation in adult survival is buffered against environmental variability, although extreme climate conditions such as storms significantly affect adult survival. The effect of climate at large spatial scales on adult survival during the nonbreeding period may lead to synchronization of variation in adult survival over the species' range and has large effects on the meta-population trends. One can thus worry about the future of such long-lived seabirds species under the predictions of higher frequency of extreme large-scale climatic events.     

Reproductive and developmental biology of the oriental cockroach Blatta orientalis (Dictyoptera)

At 27 degrees C and 45% r.h. in the laboratory, the oriental cockroach Blatta orientalis (L.) developed to adulthood in seven to nine instars for males (66% had eight instars) and eight to ten instars for females (67% had nine instars) in mixed groups, with up to twelve instars for isolated females. Nymphal development lasted 185 +/- 2 days for males, 216 +/- 4 days for females, with 89% survival to adulthood. Adult longevity was significantly more for males than females in mixed groups. Virgin females lived for 135 +/- 6 days compared with 87 +/- 9 days for females kept with males. After an initial maturation time of 12.2-13.5 +/- 0.4 days for mated and unmated females, oothecae were produced, on average, every 6-7 (range 2-29) days. Ootheca viability was 68% from females kept with males, 32% from females kept apart from males. Numbers of nymphs emerging were 14.1 +/- 0.26 after 45 days from mated female oothecae 8.2 +/- 0.3 after 49 days from unmated females. With sexual reproduction the sex ratio of progeny reaching adulthood was 1.1 males per female (n = 443), whereas unmated females produced only female progency, which is consistent with parthenogenetic reproduction. Drawings of the ventral aspect of the terminalia are given to show features useful for instar determination and for distinguishing between male and female nymphs and adults of B. orientalis.