The diet of two species of Isoperla (Plecoptera: Perlodidae) in relation to season,site, and sympatry

The seasonal change in gut contents of nymphs of Isoperla grammatica and I. difformis from six streams in southern Sweden was analysed. Both species had ingested a variety of benthic prey and vegetable matter, predominantly diatoms. Some seasonality was evident with high percentages of diatoms in spring in I. grammatica, and in autumn in I. difformis. The scope of food was larger in the latter species which contained about equal proportions of vegetable matter, chironomids, mayfly, stonefly, and black fly larvae. In I. grammatica plant matter and chironomids dominated strongly, comprising > 50% of the gut contents on an annual basis, > 90 % in spring. While small nymphs of I. difformis contained a low proportion of animal matter, only gradually increasing with size, the nymphs of I. grammatica were carnivorous from very early instars. Both species switched to a temporarily strong utilization of algae in spring. This differed among sites, and appeared to reflect differences in insolation and thus the availability of algae. There was a significant negative relationship between the mean densities of Isoperla nymphs and the proportion of animal material found in the guts of I. grammatica (R ² = 0.86). Considering the density of I. grammatica alone, the relationship was weaker (R ² = 0.56). A positive correlation between predator and prey size was observed. With chironomid prey the size range increased with predator size. With simuliid prey, however, prey size increased with predator size in such a way that it suggests selection rather than just an expanding prey size range. Correlations were stronger and regression coefficients significantly higher for I. grammatica than for I. difformis. We suggest that I. grammatica, which ingests a much wider size range of prey might choose prey of optimal sizes more readily than the more synchronously developing I. difformis. Although the life cycles of the two species are staggered, overlap in size distribution indicates that competition for food could be important in spring. However, observed differences in diet should facilitate coexistence. Gut content differences might in turn be accomplished through microhabitat segregation.     

The effect of prey size and prey density on the functional response,survival, growth and development of a predatory pentatomid bug,Podisus maculiventris say

Two experiments on the nymphal predation of Podisus maculiventris were conducted using Spodoptera litura larvae as prey. First experiment: The predator nymphs divided into three groups were reared individually from second instar to adult in a small vessel. Each nymph in the groups 1, 2 and 3 was allowed to attack the serially growing larvae (these were supplied at the rate of one per day) from 3-, 5- and 7-day old after hatching, respectively. The first prey used for the group 1 was so small that it was not only insufficient to satiate the predator but also was difficult to be searched out. But these disadvantages were soon recuperated due to the rapid growth of the prey and all nymphs could survive to adults. The survival rate of third and fourth instar nymphs in the group 3 was severely affected by vigorous counterattack of older prey larvae. Second experiment: The predator nymphs were individually reared either in a small vessel or in a large one at various rates of food supply (the prey larvae of 7-day old were used). The functional response curves obtained for each instar of the predator took a saturation type within a certain range of the prey density. The saturation level specific to each instar was generally higher for the predator reared in the large vessel than in the small one. The functional response of fourth and fifth instar nymphs was accelerated at a high prey density, viz. 16 larvae per vessel. Even at the low rate of food supply, viz. one larva per day per predator, the predator nymphs could survive to adults, but the size of resultant adults were abnormally small.     

Effect of prey size on attack components of the functional response by Notonecta undulata

The number of encounters per prey, the proportion of encounters resulting in attacks, and the proportion of attacks that were successful were observed while fourth-instar Notonecta undulata nymphs preyed on smaller N. undulata nymphs. While encounters per prey and proportion of encounters resulting in attacks increased with prey size, the proportion of attacks that were successful decreased. The increase in encounter rate per prey was due in part to an increase in the predator's reactive distance to prey as prey size increased. While none of the attack parameters varied significantly with prey density, logarithmic regression of the number of encounters per unit search time on prey density suggested that prey density tends to have a positive effect on encounters per first-instar prey but a negative effect on encounters per second-instar prey. A functional response model is presented that incorporates components of the predator's attack rate as exponential functions of prey density and allows for effects of the time the predator may spend evaluating prey encountered but not attacked and time spent attacking prey not captured. Estimates of the attack parameters derived from the experimental data are used in the model to generate functional response curves for fourth-instar N. undulata preying on first- or second-instar conspecifics. The predicted curve for second-instar prey is typical type II but the curve for firstinstar prey is slightly positively density dependent at low prey densities, i.e., type III.     

Nymphal Development and Survival of Macrolophus pygmaeus Rambur (Hemiptera: Miridae) on Two Eggplant Varieties as Affected by Temperature and Presence/Absence of Prey

Nymphal development of the predator Macrolophus pygmaeus Rambur (Hemiptera: Miridae) was investigated on two eggplant varieties, Bonica and Black Beauty, in an attempt to identify the possible role that plant variety plays in the development and survival of the predator and to determine whether these biological characteristics are influenced by temperature and prey. The development of nymphs was studied in the presence and absence of the prey, Myzus persicae (Sulzer), at 15, 20, 25, 30, and 35°C, 65 ± 5% RH, and 16:8 h (L:D) photoperiod. Significant differences in the periods of nymphal development were evident in the two varieties at 15°C when M. persicae was offered as prey, and at 15 and 30°C, when there was no prey, significantly shorter periods of development were recorded on Bonica than on Black Beauty. Mortality rates of the nymphs were similar in the presence of prey on both varieties but, in the absence of prey, higher mortality rates were recorded on Black Beauty than on Bonica. In both presence and absence of prey, at 35°C, a small number of nymphs reached adulthood on Bonica, whereas no nymphs did so on Black Beauty. Therefore, the less suitable variety, Black Beauty, had a significant effect on the development and survival of nymphs of this predator, mainly in the absence of prey and at lower and higher temperatures. It is concluded that the selection of a suitable variety for the development and survival of M. pygmaeus, particularly in the absence of prey, could improve the efficiency of a biological control program in which this predator is going to be used. This is of particular importance for its establishment and effectiveness at the beginning of the growing season when temperature is relatively low and the prey is absent or scarce, as well as in summer when temperatures are high enough (around 30°C or even higher).     

Phenotypically plastic responses of green frog embryos to conflicting predation risk

Predators have been shown to alter the timing of switch points between life history stages, but few studies have addressed switch point plasticity in prey exposed simultaneously to conflicting predation pressure. We tested hatching responses of green frog (Rana clamitans) embryos subject to perceived predation risk from chemical cues released by two stage-specific predators, predicting that these predators would elicit: (1) directional hatching responses when presented independently, and (2) intermediate phenotypic responses when presented simultaneously. R. clamitans embryos in outdoor exclosures were exposed to cues from an egg predator (freshwater leeches; Nephelopsis obscura), a larval predator (dragonfly nymphs, Aeschna canadensis), and both predators in a 2 × 2 factorial experiment, and changes in hatchling size, hatchling developmental stage, and hatching time were compared to those for control embryos. Leeches alone induced embryos to hatch at a smaller size and an earlier developmental stage than controls, while dragonfly nymphs elicited a delay in egg hatching time that was associated with larger size and later developmental stage at hatching. Embryos failed to respond to simultaneous exposure to both predators, implying that responses to each occurred concurrently and were therefore dampened. Our results indicate that prey under threat from conflicting predators may manifest intermediate defensive phenotypes. Such intermediate responses may result in elevated rates of prey mortality with possible consequences at the population level.     

Transport and kinetics of diflubenzuron and pyriproxyfen in the beet armywormSpodoptera exigua and its predatorPodisus maculiventris

Transport and retention of the insect growth regulators (IGRs) diflubenzuron and pyriproxyfen in larvae of the beet armywormSpodoptera exigua (Hübner) and in nymphs of the predatory bugPodisus maculiventris (Say) were investigated. In a first experiment, the retention of orally administered [¹⁴C]radiolabeled isotopes of both compounds in fifth-instar larvae of the beet armyworm was studied. Rate of excretion of both IGRs inS. exigua caterpillars was high, with a 50% excretion time of approximately 6 h after intake. In a second experiment, the transport of the compounds from prey to predator and their retention inside the predator were studied. Fifthinstar nymphs ofP. maculiventris were allowed to feed on caterpillars that had been given contaminated food. For both diflubenzuron and pyriproxyfen, more than 80% of the amount of radiolabel applied was recovered in consumed prey. Low levels of radioactivity (c. 3% of the applied amount of radiolabel) were also found in the fluid regurgitated by the prey larvae when attacked by the predatory bugs. Relatively small amounts of radiolabel (c. 8 and 15% of the amount orally applied to the prey for diflubenzuron and pyriproxyfen, respectively) were ingested byP. maculiventris nymphs when feeding on beet armyworm caterpillars. The data suggest that the predators did not use gut content as food. The pattern of excretion in nymphs ofP. maculiventris differed between compounds. For diflubenzuron, there was a drastic decrease of radioactivity inside the predator body of around 40% within the first 6 h and then the level of retained radiolabel remained stable at 3–4% up to 72 h. For pyriproxyfen, a slow decrease of radioactivity inside the body was observed and at 72 h only 2% of the applied quantity was detected. Results of this study are discussed in relation to the findings from previous studies on the toxicity of both IGRs toP. maculiventris.     

Prey‐mediated changes in the selectivity of the predator Macrolophus pygmaeus (Heteroptera: Miridae)

When foraging in communities with mixed prey, generalist predators may be confronted with prey species that differ in quality, size and mobility and interact with one another. To examine prey selection, predation by Macrolophus pygmaeus (Heteroptera: Miridae) was recorded by providing a diet of either one or two prey species of Myzus persicae (third‐instar nymphs), Aphis gossypii (fourth‐instar nymphs), Trialeurodes vaporariorum (third‐instar nymphs) and Ephestia kuehniella (eggs). In the experiments, prey mobility, prey quality and prey biomass were considered. The biomass consumed by the predator was dependent on the combination of prey species and the quantity of biomass offered. In choice experiments with diets mixed of two prey species at equal densities, the predation to A. gossypii was significantly reduced in the presence of E. kuehniella but the rate of consumption of M. persicae, T. vaporariorum and E.kuehniella was not significantly affected by the coexistence of any other species in the mixed prey diet. When equal amounts of biomass from two prey species were provided in combination, the total consumed biomass was significantly reduced in the mixed prey diets composed of E. kuehniella eggs and aphid nymphs. Thus, under the mixed‐prey situation, prey selection by predators may be affected by interactions among prey species differing in traits such as quality, mobility and size.     

Variation in the geometry of foreleg claws in sympatric giant water bug species: an adaptive trait for catching prey?

When giant water bugs (Heteroptera: Belostomatidae) encounter prey animals that are larger than they are themselves, they first hook the claw of their raptorial legs onto the animal, and then use all their legs to pin it. The claws of the raptorial legs in giant water bugs play an important role in catching larger prey, but the relationship between the claws, body lengths of predators, and prey size has not been fully investigated. To elucidate the functioning of claws in catching prey, we investigated prey body size relative to predator size in nymphs of two sympatric belostomatid giant water bug species, the vertebrate eater Kirkaldyia (=Lethocerus) deyrolli Vuillefroy and the invertebrate eater Appasus japonicus Vuillefroy, captured in rice fields. The younger nymphs of K. deyrolli caught preys that were larger than themselves, whereas those of A. japonicus caught preys that were smaller. Younger nymphs of K. deyrolli had claws that were curved more sharply than those of A. japonicus. The more curved claws of younger nymphs of K. deyrolli probably hook more easily onto larger vertebrates and thus this shape represents an adaptation for acquiring such prey.     

Biological control ofAphis pomi [Hom.: Aphididae] ofAphidoletes aphidimyza [Dip.: Cecidomyiidae]; a predator-prey model

Predation ofAphis pomi DeGeer [Hom.: Aphididae] byAphidoletes aphidimyza (Rondani) [Dipt.: Cecidomyiidae] was simulated in Michigan apple orchards using a computer and output validated against field data collected from sleeve cages enclosing aphid infested apple terminals. Lower and upper temperature thresholds for development were 2.9 and 35°C for nymphs ofA. pomi with a mean immature developmental period of 162.3 heat units. Median survivorship of adultA. pomi was 364.3 heat units with an average fecundity of 60.7 offspring per female.A. aphidimyza egg and larval lower threshold and developmental periods were 10.5 and 25.5, 8.1°C and 65.5 heat units, respectively. Larval functional response showed Type II behavior with a y-asymptote of 45 aphids killed per predator. Multiple generation model runs performed under different initial predator: prey densities indicated that current critical predator: prey ratios used in the field for control decisions may underestimate predator efficacy.      

Prey selectivity of Piona exigua,a planktonic water mite

Summary Females, males and nymphs of Piona exigua were observed during prey capture and ingestion. The encounter radius of the mite was very small, allowing the escape of some crustaceans, such as the calanoid copepod Boeckella. Cladocerans, such as Bosmina or Chydorus, with little or no pre-contact escape response were the most vulnerable to mite predation. Preference values in size-selection experiments varied widely between individual mites. Adult mites presented with two sizes of Daphnia carinata generally preferred the smaller prey. When four sizes were presented simultaneously, however, the preferences of female mites for each size were not significantly different. Patterns of prey selection varied with predator age and sex; for example, female mites preferred Daphnia to Simocephalus, Ceriodaphnia and Chydorus, while nymphs showed a strong preference for Chydorus over Ceriodaphnia. When two prey types were present in equal proportions, differences in total prey density (range 5 or 10/1 – 30 or 50/1) did not alter preferences between the prey species. The preference of female mites for a particular prey type generally increased with increasing relative abundance of the prey type in each of three experiments (Daphnia: Ceriodaphnia, Ceriodaphnia: Chydorus, and Daphnia: Simocephalus). These results imply switching behaviour in these mites. Our results indicate the value of direct observation of predatory behaviour as an adjunct to prey selection experiments. It is also apparent that predatory behaviour in the presence of more than one prey type may not be predictable from that observed in single-prey situations. Predation rates on particular prey species were sometimes reduced in the presence of another species. The relative proportions of prey eaten when two species were present could not be predicted from the number of each species eaten when they were presented separately.     

Searching by Adalia bipunctata (L.) (Coleoptera: Coccinellidae) and escape behaviour of its aphid and cicadellid prey on lime (Tilia×vulgaris Hayne)

• 1 The paper describes the behavioural interactions between searching larvae of Adalia bipunctata and its aphid and cicadellid prey on lime (Tilia×vulgaris Hayne).
• 2 The frequency with which the predator achieves contact with cicadellid nymphs of differing ages is related to direction of predator approach and predator perception by the cicadellid.
• 3 The success of a coccinellid in contacting and capturing its aphid prey is related to the predator's size and direction of approach, the perception of the predator by an aphid and the latter's ability to escape, the effectiveness of which is discussed.

     

Biological studies of the predacious miteTyphlodromus pelargonicus a predator of the two spotted spider miteTetranychus urticae on cucumber plants [Acari: Phytoseiidae; Tetranychidae]

The predacious miteTyphlodromus pelargonicus El-Badry preyed on the different developmental stages of the two spotted spider miteTetranychus urticae Koch. The development was quickest and the number of prey consumed was highest when individuals were maintained on eggs compared with nymphs or adult female stages. The predator was able to develop and reproduce on the eriophyid miteEriophyes dioscoridis. Soliman & Abou-Awad, nymphs of the tobacco whiteflyBemisia tabaci (Genn.) and pollen grains ofPhoenix dactylifera andRicinus communis. The average number of eggs/♀/day was 1.4, 0.7, 1.2 and 0.9 on eriophyid, whitefly,Ph. dactylifera andR. communis respectively.      

The effect of mermithid parasitism on predation of nymphal Baetis bicaudatus (Ephemeroptera) by invertebrates

We investigated how infection by the mermithid nematode Gasteromermis sp. affected predation on its nymphal mayfly host, Baetisbicaudatus, by two invertebrate predators – the stonefly nymphs of Kogotusmodestus and the caddisfly larvae of Rhyacophilahyalinata. Predation trials and behavioral observations were conducted in stream-side, flow-through experimental chambers. When parasitized and unparasitized prey were offered in equal numbers, K. modestus consumed significantly more parasitized than unparasitized nymphs. R. hyalinata consumed equal numbers of both prey types. Behavioral observations of foraging K.␣modestus on parasitized and unparasitized prey suggested that the increased consumption of parasitized nymphs was due to differences in the behavior of infected mayflies in response to the predator. Specifically, parasitized nymphs drifted less often to escape an approaching predator (non-contact encounters) compared to unparasitized nymphs, which increased the number of contact encounters and attacks that occurred between K.␣modestus and parasitized prey. Because all hosts are castrated, these behavioral alterations affect only the fitness of the parasite, which is killed along with its host by invertebrate predation. We present a number of hypotheses to explain why the parasite causes increased predation on its host. These include the large size of the parasite affecting the sensory abilities of the host, the larger energetic costs of escape behavior for parasitized individuals, and natural selection from fish predation against drifting behavior by parasitized individuals. Received: 27 May 1996 / Accepted: 30 September 1996     

Predation,oviposition and longevity of the predacious mite,Agistemus exsertus Gonzalez at different prey densities of Tetranychus urticae Koch (Acari: Stigmaeidae,Tetranychidae)

The relation between some biological aspects of the predatory mite, Agistemus exsertus Gonzalez and nymph densities of Tetranychus urticae Koch was studied in the laboratory. Predation and oviposition of A. exsertus showed Holling's Type II functional and numerical responses to changes in prey density. The total predation by A. exsertus females initially averaged 79.42 nymphs/female at 2 prey nymphs/day, significantly increased to a maximum average of 208.92 nymphs/female at 10 nymphs/day and gradually decreased to 90.92 nymphs/female at 30 prey items/day. Similarly, the predator significantly deposited total averages of 14.75, 76.42 and 34.33 eggs/female at 2, 10 and 30 nymph densities/day, respectively. The preoviposition and oviposition periods as well as longevity of A. exsertus significantly shortened with increasing prey densities.     

Prey Preference by the StinkbugPerillus bioculatus,a Predator of the Colorado Potato Beetle

Perillus bioculatus(F.) is sometimes considered a generalist but has most often been recorded as predator of Colorado potato beetle (CPB),Leptinotarsa decemlineata.(Say). This study was designed to analyze prey selection inP. bioculatuswith respect to factors that may lead to specialization. To establish if parental prey determines preference in na?̈ve progeny, prey selection experiments were conducted with the CPB and two unusual prey, the yellow mealwormTenebrio molitor(L.) and the house cricketAcheta domesticus(L.). Na?̈ve nymphs reared from yellow mealworm-fed parents in the absence of contact with the CPB initiated feeding more frequently on CPB (81.4%) than on cricket prey (69.6%) (P = 0.038), suggesting genetically inheritable preference for CPB. Progeny from CPBfed parents initiated feeding more frequently on CPB prey (93.3%) than on yellow mealworm prey (76.6%) (P = 0.0001), but progeny from yellow mealwormfed parents initiated feeding on yellow mealworm prey as frequently (89.2%) as on CPB (95.0%) (P = 0.613). Similarly, progeny from CPB-fed parents established proboscis contact more frequently on CPB (39.2%) than on house cricket prey (25.0%) (P = 0.008), whereas those from cricket-fed parents probed house cricket prey as frequently (12.5%) as CPB prey (15.4%) (P = 0.416). Results confirm specialization ofP. bioculatustoward CPB or related prey and suggest genetically inheritable as well as maternally reinforcible affinity toward CPB prey. However, affinity of na?̈ve nymphs for the CPB can be lowered by rearing parents on alternative prey, increasing their chances of survival when alternative prey must be relied upon.     

Prey preference and consumption capacity of Nephus arcuatus (Coleoptera: Coccinellidae): the influence of prey stage,prey size and feeding experience

This study examined the feeding habits of Nephus arcuatus Kapur (Coleoptera: Coccinellidae), an important predator of mealybugs in south-western Iran. The consumption capacity of male and female N. arcuatus adults was determined by their feeding on eggs, first-instar nymphs, and adult females of two destructive mealybugs, Nipaecoccus viridis (Newstead) and Planococcus citri Risso, over a 24-h period. N arcuatus consumed significantly more first-instar nymphs than eggs, and more eggs than female adults of both prey species. In addition, we also studied the developmental stage prey preference of adults reared on either N. viridis or P. citri and found that the prey preference of females did not change with the developmental stage of the mealybug. Meanwhile, the males reared on either N. viridis or P. citri showed a significant preference for the first-instar nymphs of P. citri over first-instar nymphs of N. viridis, while a preference for the eggs or adult females of these two mealybugs was not observed. This selection of first-instar nymphs by males was not tied to its previous feeding experience. Our findings suggest that prey stage, prey size and previous feeding experience had no effect on the prey selection of N. arcuatus, making it a good candidate for the biological control of mealybugs.     

Differential prey utilization by the generalist predator Coleomegilla maculata lengi according to prey size and species

Prey utilization by the generalist predator Coleomegilla maculata lengi Timb. (Coleoptera: Coccinellidae) of three sympatric lepidopterous species was quantified in relation with prey size (age) and prey species. Based on optimal foraging theory, we argued that costs associated with the utilization of small and large prey are higher than those of intermediate prey size. As a result, we expected a higher prey consumption rate on intermediate prey size leading to a convex prey consumption curve. Laboratory experiments showed that, within a given prey instar, Coleomegilla maculata lengi preyed more on Plutella xylostella (L.) compared to Artogeia rapae (L.) and Trichoplusia ni (Hübner). Generally, prey consumption rate by Coleomegilla maculata lengi on the three prey species decreased with increasing immature prey size (age). The predation efficacy of Coleomegilla maculata lengi adults and fourth instar larvae was higher compared to younger coccinellids (L2). Although, Coleomegilla maculata lengi showed a higher level of predation on smaller immature prey, we demonstrated that it is not the optimal size range for this predator. As predicted, prey weight consumption rate by Coleomegilla maculata lengi was higher at intermediate prey size leading to a convex prey utilization curve. The beneficial impact of Coleomegilla maculata lengi predation on the host plant was also estimated by using a Protection Index that considers the differential predation caused by the coccinellids and the relative importance of each pest species in terms of plant injury. Coleomegilla maculata lengi has a more significant beneficial impact when it preys on T. ni immatures.     

Tadpole–odonate larvae interactions: influence of body size and diel rhythm

Several studies have shown that prey and predator body size may affect the outcome of predator–prey interactions. However, few studies have taken in account the changes on predator–prey interactions over 24 h. In a tropical freshwater system I evaluated how predator and prey size, and their diel rhythm in activity influenced the interaction between Physalaemus pustulosus tadpoles and dragonfly larvae. Tadpoles of different size classes were exposed to two size classes of the dragonfly larvae Rhionaeschna spec. Feeding trials were conducted during day and night. Tadpole activity showed a diel rhythm and affected size-selective predation of the smallest dragonfly larvae, but not of the larger ones. Predator and prey size had a significant effect on the prey survivorship and prey size had a significant effect on the preference of the predator. The interaction between both factors was significant, indicating that they did not operate independently. I conclude that the predator–prey interactions between odonate larvae and anuran tadpoles were mainly affected by the size of the prey and the predator, and less by the diel activity pattern of the prey.     

Nymphal feeding habits of Perla madritensis Rambur 1842 (Plecoptera: Perlidae)

The diet of Perla madritensis, endemic species of the northern half of the Iberian Peninsula, is described for the first time by means of a study carried out in north-western Spain. As other species of the genus Perla, this taxon behaves mainly as predator, with Chironomidae, followed by Baetidae, being the most abundant prey in its gut. Shifts in diet composition were detected in relation to size in this species, with smaller prey being replaced by larger ones such as Simuliidae and Leptophlebiidae when the nymphs become larger.     

The brine shrimp Artemia sp. as alternative prey for rearing the predatory bug Macrolophus caliginosus

The predatory bug Macrolophus caliginosus, which is widely used in greenhouse crops, is limited in its application by its high price. An important factor in the cost is the high price of Ephestia kuehniella eggs, the prey used in their mass rearing. In order to reduce their price, alternatives to moth eggs are currently being investigated. The brine shrimp Artemia sp. is produced in large quantities in saline lakes and is fed as live food source to the larvae of a variety of marine and freshwater organisms. In this study, we tested Artemia sp. as prey for rearing M. caliginosus from two strains. We evaluated developmental and reproduction parameters of the predator when fed nauplii, enriched nauplii with a fatty acid, dry cysts and hydrated cysts, and were compared with those obtained when the predator was fed with E. kuehniella eggs. Nauplii had a significant reduction in survivorship, a delay in development of nymphs and a low reproduction of adults. Nauplii enriched with docosahexaenoic acid (DHA, 22:6n − 3), a common practice for larviculture of some marine fish species, resulted toxic to M. caliginosus nymphs and survival was quite low. On the contrary, either dry or hydrated cysts from the two strains tested of the brine shrimp produced the same nymphal survivorship, nymphal development time and weight and fecundity of adults as those obtained with E. kuehniella eggs. Demographic parameters of the eighth generation of the predator reared with cysts of the two strains, either dry or hydrated, were as good as those of moth eggs. We concluded that Artemia sp. cysts were a good substitution prey for the mass rearing of M. caliginosus.