Growth and sex maturation of a population of Saccostrea palmula (Mollusca: Bivalvia), Costa Rica

Growth and sexual maturity in Saccostrea palmula were studied between May 1998 and May 1999, in Morales estuary, Punta Morales, Puntarenas, Costa Rica (n = 540 individuals according to sample size equation). The weight-length relationship for the population was Pt = 2.13 x 10(-2) Lt1.6602 and von Bertalanffy growth function was Lt = 68.2 (l- e -0.1577 t). The mean sex ratio was 1.00 male: 0.92 females with sexually mature individuals found throughout the year. Spawning activity was highest between November and January. The mean condition index (IC = PCF/PV x 100) for the population was 121.53 +/- 2.24 and the mean meat yield was 10.32 +/- 1.64%.     

Composition, growth and conditionindex for a population of Poecilia reticulata (Pisces: Poeciliidae), in a pond in Heredia, Costa Rica

A pond population of Poecilia reticulata was studied in Santo Domingo, Heredia, Costa Rica, between September and November of 1998. The sex ratio was 1:0.49 (males:females). The mean total length was 34.43 +/- 7.26 mm for females, 23.50 +/- 2.24 mm for males and 12.27 +/- 3.41 mm for juveniles. The mean total weight was 0.69 +/- 0.48 g for females: and 0.16 +/- 0.05 g for males and 0.026 +/- 0.027 g for juveniles. The total length-weight relationship for the total population was P= 6 x 10(-5) Lt 3.3272 (r2 = 0.9613). The condition index equation was K = 25.755 e(0.004Lt) (r2 = 0.8925) for females and K = 26.767 e(0.003Lt) (r2 = 0.907) for males. The mean condition index was 31.29 +/- 0.55% for females and 28.52 +/- 0.19% for males. Both sexes reached the sexual maturity when the males and females overcame the 20.00 mm and 23.5 mm of Lt respectively.     

Natural and cultured populations of the mangrove oyster Saccostrea palmula from Sinaloa, Mexico, infected by Perkinsus marinus

The mangrove oyster Saccostrea palmula coexists with the pleasure oyster Crassostrea corteziensis in coastal lagoons of northwest Mexico. Recent discovery of Perkinsus marinus infecting the pleasure oyster in the region prompted evaluation of S. palmula as an alternative P. marinus host. An analysis to determine the possible presence of P. marinus in natural and cultured populations of S. palmula at four coastal lagoons in Sinaloa, Mexico was carried out during October-November 2010. Tissues from apparently healthy S. palmula were evaluated using Ray's fluid thioglycollate method (RFTM), which revealed a Perkinsus sp. to be present in all four locations at 6.7-20.0% prevalence. Histopathological analysis of these specimens showed tissue alterations and parasite forms consistent with moderate P. marinus infection, which was confirmed by ribosomal non-transcribed spacer (NTS)-based PCR assays on DNA samples from oysters positive by RFTM and histology. DNA sequencing of amplified NTS fragments (307 bp) produced a sequence 98-100% similar to GenBank-deposited sequences of the NTS from P. marinus. Fluorescent in situ hybridization for Perkinsus spp. and P. marinus corroborated the PCR results, showing clear hybridization of P. marinus in host tissues. This is the first record of P. marinus infecting a species from genus Saccostrea and the first record of the parasite from coastal lagoons in Sinaloa, Mexico.     

Reproduction characteristics of a stunted population of rudd, <Emphasis Type="Italic">Scardinius erythrophthalmus</Emphasis> (Linnaeus, 1758) living in the Anzali Lagoon (the southwest Caspian Sea,Iran)

A total of 486 specimens of Scardinius erythrophthalmus caught in the Anzali lagoon, a large lagoon located in the southwest Caspian Sea (Iran), between March and June 2007 were examined. Age determination showed that the maximum ages observed were 4+ in males and 5+ in females. Isometric growth was identified from length-weight relationship in males, females and pooled data. There was no significant difference from parity in the overall sex ratio of 252 males to 234 females. The fish spawn from mid April to late May, with peak spawning in mid May with the highest average GSI value of 7.12 and 13.52 for males and females respectively. The absolute fecundity ranged between 1482–59620 eggs with the mean of 9287.87 eggs while relative fecundity ranged from 127.8 to 1737.6 eggs/g with the average of 709 eggs/g of body weight. Egg diameter ranged from 0.43 to 1.23 mm with a mean of 0.73 mm. The characteristics of rudd in the stunted population from the Anzali lagoon differ markedly from those of other localities of its range.     

Breeding and growth of the inbred strain of seizure-prone Mongolian gerbils (Meriones unguiculatus)

Recently a Mongolian gerbil has become a useful laboratory animal, while little of the basic data are known about the breeding and growth of this laboratory rodent. In our animal center, an inbred strain of the seizure prone gerbil has been produced and kept these ten years. The data on the breeding and growth of the animal were obtained and described as following in the present paper. The mean life span was 26 +/- 14 month old for males and 27 +/- 13 month old for females. The mean body weight of the Mongolian gerbils at 16 weeks of age was 72 +/- 5.6 g for males and 62 +/- 7.3 g for females. The mean litter size at birth was 4.8 +/- 1.7 head. (range; 1-9) More newborn pups were born in the warm seasons (March-October) than the cold seasons (November-February). The mean rate of weaning was 80.2%. The man litter size was relatively constant in each generation.     

Observations on thermoregulatory ontogeny of mink (Mustela vison)

(1) We measured cooling rate for neonatal mink during a 10min coldroom (3.9 degrees C) exposure and subsequent warming rate during a 20min incubator (37.2 degrees C) exposure, the behaviour of the kits and the changes in their pelage between 1 and 46d of age, in an attempt to monitor the ontogeny of their thermoregulatory capacity. (2) Body weight of the 1d old kits averaged only 12.8+/-2.3g (n=4), but they gained weight rapidly reaching 226.1+/-28.3g (males, n=4) and 207.6+/-16.1g (females, n=4) at 30-31d of age, and 562.3+/-43.2g (males, n=3) and 435.7+/-35.5g (females, n=4) at 45-46d of age. (3) Body cooling rate (C(rate) ( degrees C/min); n=80) was affected by the age (between 1 and 31d), BW, initial rectal temperature (T(r0)), and sex of the kits, in addition to their body posture (P(cold), 1=extended, 2=curled-up) during coldroom exposure. C(rate) ( degrees C/min)=-0.34-0.02age-0.002BW+0.05T(r0)-0.06sex-0.20P(cold) (R(2)=0.75). (4) Body warming rate (W(rate) ( degrees C/min); n=80) was influenced by the age(2) and rectal temperature of the kit after the coldroom exposure (T(r10)). W(rate)( degrees C/min)=1.24+0.0002age(2)-0.04T(r10) (R(2)=0.76). (5) Kit fur fibre length increased from 5.45+/-0.63mm (males, n=2) and 6.20+/-0.20mm (females, n=3) at 22-23d of age to 9.43+/-1.44mm (males, n=4) and 8.70+/-1.89mm (females, n=4) at 30-31d of age, and to 12.93+/-0.47mm (males, n=3) and 11.38+/-0.41mm (females, n=4) at 45-46d of age, the growth averaging about 0.26mm per day. (6) Under normal circumstances newborn mink kits are hypothermic.Their thermoregulation develops only gradually and is dependent on increase in body mass, insulation and behavioural thermoregulation. Their strategy of survival is based on the ability to withstand hypothermia and on the nutrition and warmth provided by the dam.     

Dana swimming crab growth Callinectes danae (Decapoda: Portunidae) from Margarita Island, Venezuela

Callinectes danae is a common species captured with crab traps in nearby areas of coastal lagoons in Margarita Island. Although its considerable economic importance as a fishery resource, few studies have been done on population dynamics and its fishery potential in local coastal environments to support decision making in fishery administration. We present growth pattern details of Callinectes danae to better estimate its population size and exploitation feasibility. For this, we analyzed a total of 3 623 specimens that were monthly captured in crab pots by artisanal fishermen in Las Marites lagoon, from October 2007 to September 2008. The length-weight ratio was determined, and growth parameters estimated from both length and weight curves of the von Bertalanffy model. The general sex ratio showed no significant difference between males and females (chi2 = 0.04, p > 0.05). However, values of slopes b between males and females were significantly different (t(s) = 2.75, p < 0.05), as well as intercepts a (t(s) = 2.44, p < 0.05). Thus, the length-weight ratio was determined separately: W = 7.48e(-5)*L(2.98) for males and W = 1.21e(-4)*L(2.87) for females, indicating a negative allometric growth in both sexes. Growth parameters were established as: L(infinity) =134.80mm, W(infinity) = 166.04g and k = 0.86/yr for males; L(infinity) = 122.35mm, W(infinity) = 118.45g and k = 0.63/yr for females. Lifespan was estimated at 3.05 years for males and 4.24 years for females. We concluded that Callinectes danae is a species with short lifespan and moderately rapid growth. The coefficient of variation values (CV), of the phi-prime growth performance index (?'), showed a different growth pattern compared to those obtained in other regions. We propose that a management strategy will be the periodical review of the minimum capture size for fishing area, after the great variability found in growth parameters.     

Problem drinking among university students in Malawi

A survey of 787 University of Malawi students (481 males and 306 females) using the Alcohol Use Disorders Identification Test (AUDIT) indicated that about 72% of responders (78% of males and 63% of females) drink alcohol. The mean AUDIT score was 3.4+/-5.3 for females and 13.2+/-8.9 for males. Some 54.1% of males and 16.5% of females had the AUDIT score above the threshold level of 8.0, which corresponded with high mean values of alcohol consumption per week (222.8+/-162.7 g of pure ethanol for males and 100.3+/-98.3 g for females). In addition, about 74.4 % of male students and 27.3% of females reported episodes of heavy drinking. The findings stressed the need for developing of alcohol control policies in the University of Malawi and in the country as a whole.     

Fertility, fecundity and gonadosomatic index of Poecilia reticulata (Pisces: Poeciliidae) in Heredia, Costa Rica

Between September and November of 1998, 1 432 females of Poecilia reticulata were collected in a pond in Santo Domingo, Heredia, Costa Rica. The average total length of females was 34.43 +/- 7.26 mm (range 17.80 and 51.50 mm) and the average total weight of 0.69 +/- 0.48 g (range 0.06 and 2.32 g). This species is a viviparous matrotrofic and the specimens were sexually mature. The total length-fertility relationship was F = 0.527e 0.1171Lt (r2 = 0.9404). The average fertility was 56.1 +/- 43.6 (eggs + embryos) (range 8.0 and 197.6). The total length-fecundity relationship was Fo = 0.695e(0.1076Lt (r2 = 0.9376). The average fecundity was of 49.0 +/- 36.0 (oocytes + ova) (range 7.0 and 179.0). The total length-gonadosomatic index relationship was IGS = 0.0014 e0.134 Lt (r2 = 0.8581). The average gonadosomatic index was 0.25 +/- 0.27% (range 0.02 and 1.31%).     

Seasonal variations of plasma prolactin and LH concentrations in the female blue fox (Alopex lagopus)

A heterologous radioimmunoassay system developed for the rabbit and suitable for a wide range of mammalian species has been shown to measure prolactin in the plasma of the blue fox. Evaluation of prolactin levels throughout the year showed the concentrations displayed a circannual rhythm with the highest values occurring in May and June. Prolactin concentrations remained low (approximately 2.5 ng/ml plasma) from July until April with no consistent changes found around oestrus (March-April). In 8 pregnant females, the prolactin increase in late April and May coincided with the last part of gestation and lactation: concentrations (mean +/- s.e.m.) increased to 6.3 +/- 0.6 ng/ml at mid-gestation, 9.7 +/- 2.1 ng/ml at the end of gestation and 26.7 +/- 5.0 ng/ml during lactation. In 10 non-pregnant animals, the mean +/- s.e.m. values were 7.2 +/- 1.2 ng/ml in April, 8.8 +/- 2.2 ng/ml in May and 9.8 +/- 1.3 ng/ml in June. The prolactin profile in 4 ovariectomized females was similar to that observed in non-pregnant animals, but the plasma values tended to be lower during the reproductive season (April-June). In intact females, the only large LH peak (average 28 ng/ml) was observed around oestrus. During pro-oestrus, baseline LH levels were interrupted by elevations of 3.1-10.4 ng/ml. During the rest of the year, basal levels were less than 3 ng/ml. In ovariectomized females, LH concentrations increased within 2 days of ovariectomy and remained high (35-55 ng/ml) at all times of year.     

Biological parameters and damage by Macrosoma tipulata Hübner (Lepidoptera: Hedylidae), in cupuaçu tree [Theobroma grandiflorum (Wild ex Spreng Schum)] in Amazonas, Brazil

Biological aspects of the caterpillar Macrosoma tipulata Hübner and its damage to young leaves of Theobroma grandiflorum (Wild ex Spreng Schum) were studied under laboratory conditions of 24.5 +/- 0.7 masculineC, UR 61.6 +/- 9.1% and 12h photophase. The larval stage presented five instars with a total duration of 15.9 +/- 4.31 days, and survival of 98%. The pupal period stage was 7.0 +/- 0.56 days for males and 6.9 +/- 0.56 days for females, with 99% survival for both sex. The pupal mean length was 18.9 +/- 0.89 mm for males and 19.1 +/- 1.13 mm for females. The mean longevity of the adult was 10.3 +/- 2.25 days. The vertical distribution of damage was relatively uniform, with a tendency of greater defoliation in the middle of the treetop, but without significant difference among the three positions.     

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.     

Serum haptoglobin concentrations in ringed seals (Pusa hispida) from Svalbard, Norway

Haptoglobin (Hp) levels were measured in blood serum from 185 apparently healthy ringed seals (Pusa hispida) from Svalbard (age range, 1-30 yr) collected during the spring seasons of 2002 through 2004. The Hp concentration was 0.26 +/- 0.02 g/l (mean +/- SE; range, 0.0-1.5 g/l). Maturity status, body condition index (CI), interactions between CI and maturity status, and sex and maturity status all had significant influences on Hp levels. Mature males had significantly higher Hp concentrations compared with mature females (0.30 +/- 0.03 vs. 0.17 +/- 0.01 g/l, F(1,16) = 14.9, P<0.01). No differences were found between Hp levels in immature male and female seals (0.33 +/- 0.06 g/l). The Hp levels increased significantly in immature seals when the CI decreased. Despite the fact that mature males had a significantly lower CI than mature females, no direct correlation was found between Hp concentration and CI among adults. The elevated Hp values found in mature males might be related to injuries inflicted among males while fighting during the mating season or to high stress levels related to mating competition. The Hp concentrations of ringed seals measured in this study are useful baseline data for development of a diagnostic tool for future monitoring of the general health of this and other ringed seal populations.     

The results of studies of the red snow crab Chionoecetes japonicus from the bathyal zone of the central Sea of Japan

This study of the deep-sea red snow crab Chionoecetes japonicus is based on materials that were collected from its poorly surveyed or earlier unknown habitats in the central Sea of Japan, including the KitaYamato Bank and the top of the Peter the Great Seamount, during a research cruise aboard the R/V Vladimir Safonov in April and May of 2012. The results are compared to the data of the previous studies aboard the fishing vessels Seisho-maru 68 (September and October 1992), Viera (May and June 2005), and the Arctic Orion (April and May 2007). The red snow crab stock on the Kita-Yamato Bank has declined by one-third within 2 decades. Both males and females formed the densest aggregations at depths of 800–1040 m. The total biomass of legal-sized males in 2012 is estimated at 7400 t. The first data on red snow crab that inhabit the top of Peter the Great Seamount show that its total biomass over the area of 1.5 km2 is 14 t. The mean carapace size of crabs from the Peter the Great Seamount is smaller (males, 83.0 mm and females, 58.6 mm) than that of individuals from the Kita-Yamato Bank (males, 99.9 mm and females, 65.0 mm).     

Reproduction in captive female Cape porcupines (Hystrix africaeaustralis)

Captive females attained sexual maturity at an age of 9-16 months and conceived for the first time when 10-25 months old. Adult females were polyoestrous but did not cycle while lactating or when isolated from males. The length of the cycle varied from 17 to 42 days (mean +/- s.d. 31.2 +/- 6.5 days; n = 43) and females experienced 3-7 sterile cycles before conceiving. Pregnancy lasted for 93-94 days (93.5 +/- 0.6 days; N = 4) and litter intervals varied from 296 to 500 days (385 +/- 60.4; n = 10). Litter size varied from 1 to 3 (1.5 +/- 0.66; n = 165) and the well-developed precocial young weighed 300-440 g (351 +/- 47.4 g; n = 19) at birth. Captive females reproduced throughout the year with most litters (78.7%; n = 165) being produced between August and March.     

Biennial reproductive cycle in an extensive matrotrophic viviparous batoid: the sandyback stingaree Urolophus bucculentus from south-eastern Australia

Urolophus bucculentus, the largest urolophid species found in southern Australia, exhibits a biennial reproductive cycle. Ovulation occurs during October to January followed by a 15-19 month period of gestation followed by parturition during April to May and a short rest period while the ovarian follicles continue to develop for subsequent ovulation. Male breeding condition peaks during April to June to coincide with the period of parturition. Urolophus bucculentus has the highest matrotrophic contribution reported for any urolophid species, with a mean wet mass gain from egg in utero (4 g) to full-term embryo in utero (250 g) of c. 6250% (maximum c. 7200%), and perhaps explains the biennial female reproductive cycle where 50% of females contribute to each year's recruitment. Litter size (one to five) increases with total length (L(T) ). Females reach a longer maximum L(T) (L(Tmax) ) than do males (885 v. 660 mm). The L(T) at maturity for males and females at 50% mature (L(T50) ) is c. 414 mm (63% of L(Tmax) ) for males and c. 502 mm (57% of L(Tmax) ) for females, length at maternity indicates that recruitment production occurs later in life at c. 632 mm L(T) (71% of L(Tmax) ).     

Seasonal population dynamics of Pallisentis (Neosentis) celatus (Acanthocephala: Quadrigyridae) in the intestine of the rice-field eel Monopterus albus in China

Studies on the seasonal population dynamics of Pallisentis (Neosentis) celatus (Acanthocephala: Quadrigyridae) in the intestine of the rice-field eel Monopterus albus from the paddies and ditches in the Dong-ting Lake basin of China, were carried out with samples taken from June 2002 to May 2003. Prevalences were above 21% in all seasons sampled and with a distinct seasonal trend, which was highest (45.81%) in the spring and decreased by degrees. The mean intensity of infection was above 4.0 worms per fish. The maximum intensity of worms recovered from a single fish was 86 in the autumn of 2002. No significant seasonal differences were found in mean intensities, and differences in the mean abundance between winter and spring, winter and autumn were significant. Over-dispersed distributions of P. (N.) celatus in the host population, due to heterogeneity and feeding habits, were observed in all seasons. The size composition of both sexes of P. (N.) celatus showed males between 2.0 mm and 14.0 mm and females between 2.2 mm and 22.2 mm, with the main recruitment phase in the worm populations occurring in the summer and autumn, especially in the autumn, with the lowest recruitment occurring in the winter. The maturation and copulation of worms were mainly focused in the spring season. The sex ratio of female to male was both high in summer (1.09:1) and autumn (1.08:1). The higher proportion of females and the change in the worm sex ratio in summer can be attributed to the reduced longevity of male worms. As immature male worms exhibit a higher proportion of the worm population than females in all seasons, further studies are needed to determine if such a situation compensates for the shorter life span of males.     

Seasonal reproductive characteristics of female and male Jackson's hartebeest (Alcelaphus buselaphus jacksoni)

This project examined reproductive characteristics of female and male Jackson's hartebeest (Alcelaphus buselaphus jacksoni), a subspecies that originates in Africa and is currently a model for studies of endangered hartebeest subspecies. Progestagen concentrations were measured in fecal samples collected thrice weekly for 1 year from three non-pregnant, adult females, in the Northern Hemisphere (31 degrees 37'N, 81 degrees 09'W). When their ovaries were active, the females exhibited regular luteal cycles with an overall mean (+/-S.D.) cycle length of 21.4+/-4.1 days (n=31 luteal phases). Peak luteal progestagen concentration was 1.73+/-0.63mug/g, with a nadir concentration of 0.79+/-0.24mug/g. Cyclic activity ceased from 6 April to 28 June, 7 April to 8 July, and from 18 February to 20 August, for the three females, respectively. During this acyclic period, mean progestagen concentration was 0.90+/-0.23mug/g. Ejaculates were collected by electroejaculation from seven males throughout all seasons, with mean (+/- S.D.) 40+/-18% motility, 4.1+/-0.19 progressive motility (scale, 0-5), 1373+/-826x10(6)sperm/mL, and 42+/-28% morphologically normal sperm. These data characterized basic reproductive traits for Jackson's hartebeest and established the females as spontaneously ovulating and seasonally polyestrous when housed in the Northern Hemisphere, whereas males produced apparently viable sperm throughout the year.     

Development of the tropical fish Xenomelaniris brasiliensis (Pisces: Atherinidae) from embryo to larva and time to metamorphosis

Embryonic-larval development, and metamorphosis larval time, were studied in the tropical fish Xenomelaniris brasiliensis. Twenty nine sexually mature specimens were used, 16 females (10.86+/-1.01 cm and 7.63+/-2.62 g) and 13 males (10.43+/-0.57 cm and 6.54+/-1.44 g) which produced gametes through abdominal massage. Fertilized eggs were spherical (1.18 +/-0.44 mm diameter), greenish, transparent, benthonic and vitelus-rich; rugose striated chorion with numerous external filaments randomly distributed and abundant oil globules (0.11 + 0.07 mm diameter). The embryonic development was finished at 26.36+/-2.03 degrees C, 39.67+/-0.58 PSU and pH 8.30+/-0.10. Larvae (4.56+/-0.97 mm total length) hatched at 143 hours and 19 minutes. with vitteline sac vestiges and a single oil globule. The larvae were fed on Brachionus plicatilis and Isochrysis galbana. After the second week .4rtemia nauplii were added and I. galbana maintained. Flexion started 13 days after larvae hatched (6.10+/-1.54 mm total length) and was completed 32 days later (11.25+/-1.87 mm total length) with the hipural complex completely developed. In conclusion, X brasiliensis showed direct larval development and started larval metamorphosis (13.08+/-2.07 mm total length) to juvenile 40 days after hatching.     

Evaluation of Aprostocetus hagenowii (Hymenoptera: Eulophidae) for the control of American cockroaches (Dictyoptera: Blattidae) in sewers and crevices around buildings

The objective of this study was to evaluate the potential of Aprostocetus hagenowii (Ratzeburg) (Hymenoptera: Eulophidae) to control American cockroaches, Periplaneta americana (L.) (Dictyoptera: Blattidae), in sewer manholes and in crevices around buildings. Parasitoids were released weekly for 12 wk from laboratory parasitized heat-killed oothecae, and parasitism monitored using sentinel oothecae of American cockroaches. In addition, preference of A. hagenowii for 1- to 4-wk-old oothecae was evaluated in the laboratory. A. hagenowii females showed no preference for any ootheca age. Twenty of the 30 tested females parasitized one ootheca, whereas the other 10 parasitized two oothecae. The total progeny (males, females, and total) that emerged from a single ootheca parasitized by a female was not significantly different to the total progeny that emerged from two oothecae parasitized by a female. The number of males, females, and total progeny that emerged from the second parasitized ootheca was significantly less than the number that emerged from the first parasitized ootheca. The weekly mean sentinel oothecal parasitism rate in wall crevices was 18.1 +/- 3.2% and in sewer manholes was 13.3 +/- 2.0%. The mean number of released A. hagenowii females per number of parasitized sentinel oothecae recorded in crevices was 189 +/- 18, whereas it was 428 +/- 50 in sewers. A. hagenowii females were more effective at parasitizing sentinel oothecae placed at high and middle levels in manholes than at a low level when releases were made at the midpoint of the manhole shaft.