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).     

Heat curing Metaseiulus occidentalis (Nesbitt) (Acari,Phytoseiidae) of a fitness-reducing microsporidium

Laboratory colonies of the predatory mite Metaseiulus occidentalis in Gainesville, FL were found to be infected with an undescribed microsporidium. Experiments were performed to quantify the effect of infection on the fitness of M. occidentalis and to determine if heat treatment can cure mites of the microsporidium. The colonies tested were derived from an isofemale line so that differences in performance could be attributed to the presence of microsporidia. A subcolony of an uninfected isofemale line was infected with the microsporidium by feeding females infected eggs from another colony of M. occidentalis. Infected mites had a shorter mean (+/-SD) female life span (7.4 +/- 2.9 vs. 10.0 +/- 2.8 days), lower mean oviposition (1.6 +/- 0.7 vs. 2.2 +/- 0.4 eggs/day), and a male-biased sex ratio (43 +/- 16% vs. 57 +/- 15% female progeny). The infection was reduced temporarily in colonies initiated from mites that were reared in a growth chamber at 33 degrees C from egg to adult, but healthy colonies only were established from the progeny of the heat-treated adults. These colonies remained free of infection for 10 weeks.     

Comparative fecundity and survival rates of Phlebotomus papatasi sandflies membrane fed on blood from eight mammal species

Female sandflies, Phlebotomus papatasi (Scopoli) (Diptera: Psychodidae), were fed via chicken membrane on heparinized blood from eight species of mammal (human, horse, cow, pig, dog, rabbit, guinea-pig, hamster) and their reproductive success rates were compared. No appreciable differences between those fed on human and animal blood were detected with respect to the proportion of flies that fed successfully, mortality-rate within 24h, number of eggs laid per blood-fed female or egg viability. When mass-rearing sandflies for research purposes, membrane-feeding avoids practical difficulties encountered if sandflies are allowed to feed on live hosts (i.e. anaesthesia, distress from handling and postfeeding inflammation) and reduction of sandfly fecundity due to host antibody interference. Use of animal blood also eliminates risks of accidental transmission of human blood-borne pathogens, e.g. hepatitis B and human immunodeficiency virus (HIV), and is less expensive than maintenance of animals and their preparation for sandfly feeding.     

Estimating carrying capacity in a newly colonized sand fly Lutzomyia serrana (Diptera: Psychodidae)

The phlebotomine sand fly Lutzomyia serrana (Damasceno & Arouck) was mass-reared tinder conditions of varying densities in an effort to improve colony production efficiency. To do this, the experimental carrying capacity of a standard rearing chamber was determined, i.e., the optimum population size in relation to density (individuals per unit of space). Rearing chambers of 100 cm3 were populated with 1-50 L. serrana engorged females and an equal number of males. Laboratory conditions were maintained at 23-26 degrees C and 85-95% RH. The following parameters were recorded for each experimental chamber (three replicates): (1) female mortality without oviposition, (2) number of eggs oviposited and (3) number of adults emerging from the egg cohort. Female mortality began to increase substantially in the 26-female chamber, from 5.7% to 15% and finally reaching 60.2% in the 46-50 female chambers. In the chambers containing 1-20 females, egg number and realized adult progeny increased linearly to reach an asymptote. In the 20-50 female chambers, the number of eggs ranged from 420 to 699, and adult production from 306 to 432. The optimum carrying capacity for the 100-cm3 chambers was 22 +/- 2 females. Beyond this number, auto-regulation was initiated, i.e., female mortality without oviposition increased as the number of females per chamber increased. Total number of eggs and adult production was similar in all chambers containing 20-50 females. In conclusion, for optimizing production of mass reared sand flies, determination of the carrying capacity is essential to optimize use of insectary resources, to avoid loss of valuable potentially ovipositing females, and to increase overall production efficiency.     

Development and reproduction of Podisus distinctus (Heteroptera: Pentatomidae) fed on larva of Bombyx mori (Lepidoptera: Bombycidae).

Biological control has been reducing the use of chemical products against insect pests, especially predatory Pentatomidae. Species of this group can present high variations in their life cycle as a result of their diet. Thus, the objective of this research was to study nymph development and reproduction of Podisus distinctus (St?l, 1860) (Heteroptera: Pentatomidae) fed on Bombyx mori L., 1758 (Lepidoptera: Bombycidae) larvae (T1), compared to those fed on Tenebrio molitor L., 1758 (Coleoptera: Tenebrionidae) (T2) and Musca domestica L., 1758 (Diptera: Muscidae) larvae (T3) at a temperature of 25 +/- 0.5 degrees C, relative humidity of 70 +/- 2%, and photophase of 12 h. Predators fed on B. mori showed duration of the nymph phase (18.68 +/- 1.02) similar to those fed on T. molitor (18.32 +/- 1.49). Pre-oviposition and oviposition periods and number of egg masses, besides eggs and nymphs per female, were higher with B. mori (5.83 +/- 2.02; 15.00 +/- 7.40; 8.42 +/- 1.84; 296.69 +/- 154.75; and 228.55 +/- 141.04, respectively) while longevity of males and females of P. distinctus was 25.76 +/- 16.15 and 35.00 +/- 16.15 days with T. molitor, and 20.57 +/- 13.60 and 23.46 +/- 12.35 days with B. mori, respectively.     

Reproductive biology of Fidiobia dominica (Hymenoptera: Platygastridae), an egg parasitoid of Diaprepes abbreviatus (Coleoptera: Curculionidae)

The reproductive biology of Fidiobia dominica Evans (Hymenoptera: Platygastridae) was studied in the laboratory (25.6 +/- 1 degrees C) using host eggs of Diaprepes abbreviatus L. (Coleoptera: Curculionidae). F. dominica readily parasitized D. abbreviatus eggs on both host plant and wax paper substrates. The number of egg masses parasitized and the number of offspring produced were higher when females were offered more than one host egg mass but did not differ when either two or three egg masses were offered. Female parasitoids that were provided with host eggs and a honey food source lived significantly longer than those that were not provided a food source; however, they did not parasitize more D. abbreviatus eggs. Oviposition occurred in host eggs from 0 to 7 d old, and host mortality was relatively consistent for eggs 0-5 d old and lower for eggs 6-7 d old. Successful parasitoid emergence seldom occurred after host eggs were 4 d old, and by 7 d, no adults successfully emerged. Developmental time from egg to adult was 19.3 +/- 0.2 d for males, significantly more rapid than the females (20.4 +/- 0.1 d). The mean longevity of adult females was 8.0 +/- 0.4 d, with a mean oviposition period of 2.7 +/- 0.3 d; males survived 8.1 +/- 0.4 d. The demographic parameters including intrinsic rate of increase (r(m)), generation time (T), and net reproduction (R(o)) were 0.142/d, 22 d, and 22.4 female eggs/d, respectively.     

Mutual Interference Among Female Anagyrus kamali Moursi (Hymenoptera: Encyrtidae) and its Impact on Fecundity, Progeny Production and Sex Ratio

The solitary endoparasitoid Anagyrus kamali Moursi was introduced to the Caribbean to control populations of Hibiscus Mealybug (HMB) Maconellicoccus hirsutus Green. As part of a biological control programme, mass rearing of A. kamali should produce a maximum of good quality female wasps, because only female parasitoids attack the mealybug. In laboratory experiments conducted at 27 +/- 2°C, mutual interference between female parasitoids on the total oviposition, progeny production and sex ratio was assessed at five parasitoid densities: i.e. 1, 2, 5, 10 and 20 female wasps per 50 mealybugs. Oviposition rates of females decreased with increasing female density, without significantly affecting the sex ratio (average across densities of 0.49 +/- 0.322) (male/female). Under mass-rearing conditions, an increase of the female density from 25 to 75 individuals per cage resulted in an increase of the progeny production from 266 +/- 70.1 to 877.5 +/- 393.3 parasitoids. From 75 to 100 females released per cages, the progeny production was not significantly different with 877.5 +/- 393.3 and 965.3 +/- 608.3 parasitoids produced, respectively. Regardless of the female density, progeny sex ratio remained stable at an average of 0.45 +/- 0.095. As a result, the best efficiency of the mass-production system was obtained at a density of 75 females per cage. However, parasitoid production at this density was inferior to singly caged females by about 50%.     

Reproductive physiology of Anopheles gambiae and Anopheles atroparvus.

When exposed to a human host, Anopheles gambiae started probing 4 h post-eclosion, but 95% successfully blood-fed by 16-20 h with maximal blood volumes of 5- 10 microl per female. When fed sugar, the 95% feeding was not observed until 36-40 h post-eclosion; sugar meals appeared to interfere with blood meals. Similarly in An. atroparvus, maximum volumes were 10 microl when starved but only 6 microl when fed sugar. This species did not bite before 2 d, and 95% biting was by 4 d. Given single blood meals to water-kept An. gambiae, a threshold body size for oogenesis was detected. With wing lengths below 2.8 mm, eggs never matured, but when sugar-fed, females of all sizes matured eggs including the synthesis of maternal deposits. Although sugar feeding interfered with blood feeding, more lipid was transferred to the yolk. In water-kept An. atroparvus only 5% of the females produced eggs. When sugar-fed for 4 d, all females matured eggs, so in this species sugar feeding appeared to be essential for oogenesis. An. gambiae always took multiple blood meals, tested at any time after the first ones, leading to 120 mature eggs/female. Yolk composition was 3.9 mcal protein and 3.8 mcal lipid/oocyte when kept on water, but 2.8 meal protein and 4.3 mcal lipid/oocyte with intermittent sugar meals, thus marking a surprising flexibility in synthesis of yolk protein and lipid that strongly depends on additional carbohydrates sources. Only 80% of water-fed An. atroparvus re-fed 2 d after a first blood meal with small females taking three blood meals but they still showed reduced fecundity. Only the large water-fed females matured eggs, with blood volumes higher than 9-12 microl. When fed sugar, the blood meal input was reduced, but oogenesis was possible, whereas water-fed females required three blood meals to reach the caloric level comparable to pre-feeding sugar-fed females. Water-fedAn. gambiae could survive on daily blood meals alone, but survival was further extended by intermittent sugar meals. When offered a blood donor daily, there was a behavioral difference. Females maintained alone showed a more or less regular 3 d feeding and oviposition activity, while females kept in groups fed daily followed a daily oviposition pattern, suggesting gonotrophic discordance.     

Immunization of rabbits with faecal extract of Pediculus humanus, the human body louse: effects on louse development and reproduction

Abstract Immunization of rabbits with a faecal extract of the human body louse (Pediculus humanus) induced a high titre of specific IgG. The mean weight of Wood taken by females fed on the immunized rabbits was significantly lower (29%) than taken by females fed on the control rabbits. The mean number of eggs per female fed on the immunized rabbits was significantly lower than for females fed on the control rabbits. The hatchability of the eggs laid by lice fed on immunized rabbits (91%) was significantly lower than of those fed on control rabbits (94%). The rate of development of nymphs fed on control rabbits was significantly higher than those fed on the immunized rabbits. There was no difference in survival rates of lice fed on immunized and control rabbits.     

Development,survival, body weight,longevity, and reproductive potential of Oemena hirta (Coleoptera: Cerambycidae) under different rearing conditions

Oemona hirta (F.) is a New Zealand native longicorn beetle, whose larvae bore into the wood of branches and stems of living trees and vines, causing serious damage. To explore effective methods for maintaining laboratory colonies and biology of immature stages of this species we evaluated four laboratory rearing methods with both natural and artificial diets and compared biological parameters of laboratory colonies with those of field-collected insects. On an artificial diet, approximately 40% of neonate and 70% of autumn- and 11% of winter-collected larvae reached adulthood. Neonate larvae could not complete their development in cut poplar (Populus nigra variety italica Koehne) twigs; however, when twigs were standing in water >46% of neonate larvae survived to adulthood. Mean larval development time ranged from approximately150 to almost 300 d, depending on rearing methods. Mean pupal stage ranged from 15 to 19 d. Adult females were significantly heavier than males. Although adult females from field-collected twigs and reared on the artificial diet had similar mean body weight, which was significantly greater than that of other rearing colonies, the potential fecundity was the highest in the former (83.1 +/- 29.4 eggs) and the lowest in the latter (33.5 +/- 9.1 eggs). In all laboratory-reared and field-collected insects, the total number of eggs produced (eggs laid + eggs that remained in dead female body) by females was positively correlated with their body weight. When larvae fed on the artificial diet, there was no positive correlation between the number of eggs successfully laid and female body weight. However, when larvae lived on natural food, a positive correlation was found. In laboratory colonies, mean longevity of females (36 to 52 d) was slightly greater than that of males (30 to 50 d) without significant difference between sexes but in the adults from field-collected twigs, males (52 d) lived significantly longer than females (33 d). In terms of time, labor, and the number of resulting adults, collecting larvae in the field in autumn and then transferring them onto artificial diet is the most effective method for maintaining a laboratory colony.     

Reproductive potential of field-collected overwintering boll weevils (Coleoptera: Curculionidae) fed on pollen in the laboratory

Abstract  The reproductive potential of overwintering boll weevil, Anthonomus grandis grandis (Boheman), females collected from pheromone traps in September, November and January, fed for 1, 3, and 5 weeks on plant pollens, and then provided cotton squares, was determined in the laboratory at 27 ± 1°C, 65% RH, and a photoperiod 13 : 11 (L : D) h. Duration of pollen feeding by overwintering boll weevils did not significantly influence egg and feeding punctures, or puncture ratios (egg to total punctures) for any of the three months of parent weevil collections when provided cotton squares on a daily basis. However, punctures and puncture ratios are significantly different when comparing mean data between months of boll weevil collections. When boll weevils were provided with cotton squares daily, the pre-ovipositional periods of female parents captured in September, November and January were 5, 9 and 14 days, respectively. The rate of eggs by females was significantly lower during November and January than September. Female parents collected in September produced a significantly higher percentage of eggs yielding adult progeny than those collected in November and January. Life table parameters indicated that net reproductive rate ( R _o) of boll weevil females collected in September was 1.2-fold higher than those collected in November and 10.7-fold higher than those collected in January. Except for testes size, no differences in male reproductive parameters were observed during the cotton-free period compared with males captured during mid-cotton (June). The number of oocytes in the ovarioles and the number of oocytes containing yolk were significantly lower during September, November and January compared with June. The reproductive potential of overwintering boll weevil females collected in different months is an important consideration in determining the success of any control strategy.     

Irradiation of Maconellicoccus hirsutus (Homoptera: Pseudococcidae) for phytosanitation of agricultural commodities

Studies on the tolerance of pink hibiscus mealybug, Maconellicoccus hirsutus (Green), to ionizing irradiation were undertaken to determine the dose needed to disinfest commodities of this pest. Overall, radiotolerance of M. hirsutus was found to increase with maturity. Target doses of 50 Gy reduced eclosion of eggs to <50%, but doses as great as 750 Gy did not eliminate hatching during the study. At 100 Gy, M. hirsutus eggs, crawlers, and nymphs were controlled, because progeny were not produced despite crawlers and nymphs living for much longer periods than unexposed individuals. Fecundity of treated crawlers and nymphs was greatly impacted by treatment of 100 Gy; crawlers developing into adults produced no eggs, and 10 adults of 3,983 treated nymphs (0.25%) produced 309 eggs. Few adult females exposed as nymphs deposited eggs because male nymphs died during development, which left the females unfertilized. By comparison, 89% of female nymphs treated at 100 Gy and mated as adults with nonirradiated males produced a total of 1,447 eggs (19 eggs per female). Evidence from this study suggests M. hirsutus reproduces sexually, not parthenogenetically. Adults, the most resistant stage, exposed to target doses of 100 Gy produced eggs that were 1.2% viable, from which a small portion of individuals successfully completed development and produced progeny. A target dose of 250 Gy was sufficient to control adult M. hirsutus because, at that dose, none of the eggs produced by 3,093 irradiated adults eclosed. The minimum dose needed to ensure quarantine security is between 100 and 250 Gy.     

Aspects related to productivity for four generations of a Lutzomyia longipalpis laboratory colony

A closed colony of Lutzomyia longipalpis was established with specimens collected in the Raposa - Serra do Sol indian reservoir, one of the main foci of visceral leishmaniasis in the State of Roraima, Brazil. Biological observations were made on four generations of a L. longipalpis colony with emphasis on productivity. Aspects studied were the number of laid and retained eggs, and the number of adults (male and female) per generation. During the four generations the percentage of engorged females that laid eggs varied from 64.2% (third generation-F3) to 90.3% (second generation-F2). The mean number of eggs laid per female varied from 23.6 (F3) to 39. 9 (first generation-F1). The maximum number of eggs laid per female varied from 84 (F3) to 124 (F1). The mean number of retained eggs per female was 12.7 (parental generation-P and F1) to 22.1 (F2). The number of females exceeded the number of males in all generations. However, significant difference for male/female ratio was found only for F3. Fecundity rates were between 42.1 (F3) and 58.3 (F2). From a total of 439 blood-fed females, 355 females laid 12,257 eggs that yield 5,354 adults (2,525 males and 2,829 females) in four generations. F2 presented maximum productivity and fecundity rates.     

Demography of the cereal rust mite Abacarus hystrix (Acari: Eriophyoidea) on quack grass

Demography parameters of the cereal rust mite Abacarus hystrix (Nalepa) on quack grass were studied to investigate its potential capacity of population increase in conditions of initially low density. The experiment was maintained under laboratory conditions at a constant temperature of 19.5-20.5 degrees C and 94 +/- 1% RH. Life-history data were used to calculate duration of developmental stages, survival of adults and rates of population increase. A new method of estimation of age-dependent fecundity is proposed. On average, eggs required 7.98 (n = 33, 95% CI: 7.68-8.21) days to develop into adults. Life expectancy of females was longer than that of males (9.72 and 5.41 days, respectively). The mean sex ratio, expressed as the proportion of females, was 0.80 (n = 122, CI: 0.71-0.86). The reproductive output for females was age-dependent and daily egg production reached a peak (3.83 eggs/day, CI: 2.50-5.15) on the 5th day, and then decreased steeply. The net reproductive rate (R0) was 10.12 female progeny per female per generation, the generation time (T) was 11.31 days, the intrinsic rate of increase (r) was 0.20 female progeny per female per day, and the finite rate of increase (lambda) was 1.23 female progeny per day. These estimates showed that A. hystrix has a great potential capacity for rapid population increase when colonising new hosts and its density is low. Therefore, we conclude that the population of the cereal rust mite on quack grass may rapidly build up to very high densities and can be a reservoir population, which may easily disperse and infest other, including cultivated, grasses.     

Oviposition diapause and other factors affecting the egg-laying of Phlebotomus papatasi in the laboratory

Stimuli which modulate oviposition of P. papatasi were investigated to improve insectary breeding efficiency. Oviposition and survival of gravid females were observed weekly during April-December 1987, in plastic cages at 28 +/- 1 degrees C with L:D 17:7. Oviposition of controls was subject to seasonal variation despite the relatively uniform insectary conditions. From April to mid-October (summer), mean weekly oviposition ranged from 11.6 to 18.6 eggs per fly, dropping to 1.4 eggs/fly in November (winter). Monthly yields of eggs were found to correlate with the seasonal cycle of ultraviolet (UV) radiation in sunlight. This was attributed to an endogenous rhythm since the flies were not normally exposed to UV under insectary conditions. Short exposure to UV sources of 254 nm and 312 nm, but not white light, raised the low rate of oviposition in October-November from 1.4 to 16.8-29.6 eggs/female/week, but female mortality also increased highly significantly. It is suggested that the seasonal oviposition cycle of P.papatasi is set by levels of UV irradiation. In the warm season oviposition was promoted, as compared to controls, by furrows in plaster of Paris lining the bottom of cages (29.6 v. 10.2 eggs/female) and by cow manure in the cages (39.7 v. 18.2 eggs/female), but the combination of both stimuli gave no greater fecundity (40.9 v. 20.9 eggs/female). Oviposition decreased when larvae were present (3.9 v. 15.0 eggs/female) and in half-volume cages (3.9 v. 12.5 eggs/female/week). Under standard insectary conditions, mean weekly mortality-rates of P.papatasi females were 18.3 +/- 4.8% in October-November and 36.5-59.1% during the warmer months. None of the experimental conditions yielded any significant improvement in survival-rates.     

Effects of rearing conditions on reproduction of Spathius agrili (Hymenoptera: Braconidae), a parasitoid of the emerald ash borer (Coleoptera: Buprestidae)

Spathius agrili Yang (Hymenoptera: Braconidae) can be successfully reared on emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), larvae feeding in chambers drilled in small ash twigs that are wrapped with floral tape. Females maintained in groups with males for one week can receive enough sperm for production of female progeny throughout their lives. Volatiles released by emerald ash borer adults feeding on ash foliage increased parasitoid fecundity over ash foliage alone or no stimulus. The temperature at which the parasitoids were reared ranged from 20 to 25 degrees C in a daily cycle; however, raising the daily maximum temperature to 28 degrees C did not affect parasitoid longevity or fecundity. Adult females lived between 12 and 127 d, with an average of 60.8 +/- 4.5 d. Males lived slightly longer, with an average of 66 +/- 4.5 d. The first clutch of eggs was laid when the female was between 2 and 42 d old, with the average preoviposition period lasting 11.4 +/- 1.4 or 19.5 +/- 2.0 d in 2007 and 2009 trials, respectively. A higher proportion of the emerald ash borer larvae were feeding and thus attractive to parasitoids in the 2009 trial, and female S. agrili laid an average of 9.5 +/- 1.0 clutches containing 5.4 +/- 0.2 eggs, for an average of 51.2 eggs per female. Approximately three quarters of the progeny were female. The number of eggs per clutch was significantly greater when deposited on larger emerald ash borer larvae, further highlighting the need for quality larvae in rearing. Chilling S. agrili pupae at 10 degrees C to stockpile them for summer release was not successful; chilling resulted in lower survival and lower fecundity of emerging progeny. Female S. agrili proved capable of attacking emerald ash borer larvae through even the thickest bark of an ash tree that was 30-cm diameter at breast height. Even emerald ash borer larvae that were creating overwintering chambers in the outer sapwood of the tree were successfully attacked, suggesting that S. agrili could be reared on field collected logs infested with emerald ash borer.     

Mating and prey stage affecting life history,reproduction and life table of the predacious mite Phytoseiulus macropilis (Banks) (Acari: Phytoseiidae)

Abstract

Two factors were examined to determine their effect on the life history, reproduction and life table parameters in the predacious mite Phytoseiulus macropilis (Banks) in the laboratory. The factors studied included multiple mating and various prey stages of Tetranychus urticae Koch. When females fed on mixed actives (protonymphs and deutonymphs) of T. urticae, the fecundity of females mated more than once was 1.7 times higher than in females mated only once, also oviposition period and adult longevity was longer. The adult longevity and life span of P. macropilis were similar when fed on mixed actives, eggs (0 – 24-h-old) and (0 – 48-h-old) of T. urticae, while both periods were increased and reproduction was higher when fed on older eggs (72 – 96-h-old) of T. urticae. The total number of eggs deposited by females was significantly higher on eggs of (various ages) than on mixed actives of T. urticae. Life table parameters showed that a diet of (72 – 96-h-old) eggs of T. urticae provided the longest generation time (11.066 days) and female longevity (33.54 days) as well as the highest intrinsic rate of natural increase (rm = 0.36755) and greatest total fecundity which resulted in the highest net reproductive rate (Ro = 58.4136) value. The adult female consumed daily an average of 6.8 mixed actives of T. urticae during its life cycle, while it was increased to 13.6 during the oviposition period. The daily (72 – 96-h-old) eggs of T. urticae consumed by female P. macropilis during its life cycle and adult longevity was significantly higher than that recorded on either (0 – 24-h-old) or (0 – 48-h-old) eggs of T. urticae.     

Influence of prey on developmental performance, reproduction and prey consumption of Neoseiulus californicus (Acari: Phytoseiidae)

The Spical strain of the predatory mite Neoseiulus californicus (McGregor) is used as a biological control agent, but little is known about its preferred prey and host plants in Japan. Here we studied the development, reproduction and prey consumption of the Spical strain when fed on eggs of five different spider mite species deposited on both their laboratory-rearing plant and cherry, on which all five spider mite species developed well. The developmental periods of immature N. californicus females and males were significantly affected by the prey species they fed on, but not by the plants. No difference was found between males and females. The developmental period was shorter on eggs of two Tetranychus species than on eggs of Panonychus ulmi. Immature females had a higher predation rate than immature males. Preoviposition period, oviposition period and the number of eggs laid per female were not significantly affected by either the plants or the type of prey eggs. The postoviposition period and total adult longevity were shorter on eggs of P. ulmi than of the other four prey species, but there was no effect of plant substrate. The postoviposition period of the Spical strain was much longer than that of other N. californicus strains or other predatory mite species: the postoviposition period of the Spical strain was more than three times longer than the oviposition period, accounting for more than 75% of the total adult longevity. This suggests that the females need multiple mating to reach full egg load, but this remains to be tested. Total consumption by N. californicus adults was lower for eggs of P. ulmi than for eggs of the other four species, apparently because of the shorter postoviposition period when fed on eggs of P. ulmi. The intrinsic rates of natural increase (r _m) on the rearing plant did not differ among prey species, whereas those on cherry were significantly different: the value was higher on Tetranychus urticae eggs than on eggs of other species. Only when N. californicus fed on T. urticae eggs, the r _m-values were significantly different between the rearing plant and cherry (higher on cherry). Thus, the Spical strain of N. californicus could feed on eggs of all five spider mite species, deposited on a variety of plants with similar r _m-values, suggesting that it could be successfully used to control spider mites in orchards and various crop fields of Japan.     

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.     

The effect of adult feeding on the fecundity,weight loss and survival of the pine beauty moth,Panolis flammea (D&S)

Summary Adult females of the pine beauty moth, Panolis flammea, fed on a saturated honey solution, laid significantly more eggs than those individuals given water only or not fed at all.At 20°, the longevity of both male and female moths was significantly increased when they were supplied with a food source. At 10° fed male months were not significantly longer lived than unfed moths. Fed female moths at 10° were however, significantly longer lived than unfed individuals. At 20°, fed male moths lived longer than fed females (8.17 days as compared with 5.95 days). At 10°, fed female moths lived longer than fed males (16.00 days compared with 11.41 days).At 20°, weight loss in unfed females over the reproductive period was proportional to the number of eggs laid and the survival time of the individual. In fed females, no significant weight loss occurred over the reproductive period, irrespective of the number of eggs laid or the longevity of the individual.Egg production, even in fed females, over the life span of an individual was only a fifth of the total eggs present in the reproductive tract at eclosion.It is concluded that adult females of P. flammea are likely to require an extra external food source to achieve their full reproductive potential.