Laboratory-reared Moths Research Articles

Life-History Parameters of Striacosta albicosta (Lepidoptera: Noctuidae) Under Laboratory Conditions.

Striacosta albicosta (Smith) is a key pest of maize and dry beans in North America. It has expanded its distribution from the western Great Plains of the United States to the Great Lakes region in the United States and Canada. There has been limited research on the baseline biological aspects of this insect under controlled conditions. The objective of this study was to detail the biological parameters of S. albicosta feeding on an artificial diet under laboratory conditions. Overall survival from neonate to adult at 26.6 ± 1°C was 36.72% and the total developmental time was approximately 110 d. Survival of the egg, larval, prepupal, and pupal stages were 75.71, 98.50, 51.78, and 95.10%, respectively. Average duration of the egg, larval, prepupal, and pupal stages was 4.64, 28.20, 41.50, and 25.91 d, respectively. During the larval stage, 92.50% of larvae developed through seven instars and the remaining through six instars. Larvae that developed through six and seven instars exhibited a mean growth ratio of 1.60 and 1.47, respectively; however, there was no difference in pupal weight. Eggs laid by field-mated moths showed a fertility of 75.71%, compared with 4.18% from laboratory-reared moths. These data suggest that S. albicosta develop primarily through seven instars and the most vulnerable developmental stage is the prepupa. Laboratory conditions strongly affected fertility success. Information presented here greatly expands our understanding of S. albicosta biology, which can be used to improve the efficiency of laboratory bioassays and management techniques for this critical crop pest.

How to fight multiple enemies: target-specific chemical defences in an aposematic moth.

Animals have evolved different defensive strategies to survive predation, among which chemical defences are particularly widespread and diverse. Here we investigate the function of chemical defence diversity, hypothesizing that such diversity has evolved as a response to multiple enemies. The aposematic wood tiger moth (Arctia plantaginis) displays conspicuous hindwing coloration and secretes distinct defensive fluids from its thoracic glands and abdomen. We presented the two defensive fluids from laboratory-reared moths to two biologically relevant predators, birds and ants, and measured their reaction in controlled bioassays (no information on colour was provided). We found that defensive fluids are target-specific: thoracic fluids, and particularly 2-sec-butyl-3-methoxypyrazine, which they contain, deterred birds, but caused no aversive response in ants. By contrast, abdominal fluids were particularly deterrent to ants, while birds did not find them repellent. Our study, to our knowledge, is the first to show evidence of a single species producing separate chemical defences targeted to different predator types, highlighting the importance of taking into account complex predator communities in studies on the evolution of prey defence diversity.

Effects of age, ambient temperature and reproductive status on wing beat frequency of the rice leafroller Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Crambidae)

The rice leafroller Cnaphalocrocis medinalis (Guenee) is a serious insect pest of rice with migratory ability. In this work, we studied the effects of age, temperature and reproductive status on the wing beat frequency (WBF). The longevity of this moth reached 30.6 days at 16 °C, which was significantly longer than that at 26 and 32 °C (10.7 and 8.8 days, respectively). The WBF of the 1-day-old moths did not differ significantly among the three temperature treatments. However, the WBF of the 2- to 7-day-old moths differed significantly among those temperatures, with the highest WBF at 26 °C and the lowest WBF at 32 °C. Both age and temperature significantly affected the WBF. No significant differences in WBF were detected either between mated and unmated or between parous and nulliparous female moths. There were no significant differences on WBF among field-collected females on different stages of ovary development. Significant correlations were found between the WBF and the tethered flight duration in field-collected moths as well as in laboratory-reared moths. These results indicated that the WBF was intensively influenced by age and temperature, and it may be a potential index to evaluate the flight ability of this species.

Costs and benefits of thermal acclimation for codling moth,Cydia pomonella(Lepidoptera: Tortricidae): implications for pest control and the sterile insect release programme

Sterile insect release (SIR) is used to suppress insect pest populations in agro-ecosystems, but its success hinges on the performance of the released insects and prevailing environmental conditions. For example, low temperatures dramatically reduce SIR efficacy in cooler conditions. Here, we report on the costs and benefits of thermal acclimation for laboratory and field responses of codling moth, Cydia pomonella. Using a component of field fitness, we demonstrate that low temperature acclimated laboratory-reared moths are recaptured significantly more (∼2–4×) under cooler conditions in the wild relative to warm-acclimated or control moths. However, improvements in low temperature performance in cold-acclimated moths came at a cost to performance under warmer conditions. At high ambient temperatures, warm-acclimation improved field performance relative to control or cold-acclimated moths. Laboratory assessments of thermal activity and their limits matched the field results, indicating that these laboratory assays may be transferable to field performance. This study demonstrates clear costs and benefits of thermal acclimation on laboratory and field performance and the potential utility of thermal pretreatments for offsetting negative efficacy in SIR programmes under adverse thermal conditions. Consequently, the present work shows that evolutionary principles of phenotypic plasticity can be used to improve field performance and thus possibly enhance pest control programmes seeking increased efficacy.

Sex-dependent variation in the floral preferences of the hawkmoth Manduca sexta

Studies of plant–pollinator interactions have often documented species differences in preferences for floral advertisements and rewards. However, the contribution of intraspecific variation in behaviours, especially between sexes, remains less understood. We explored resource preference and resource use by male and female Manduca sexta hawkmoths, relative to two important nectar resources in southern Arizona, U.S.A. Manduca sexta is the major pollinator of one of these species (Datura wrightii, Solanaceae). Because females must also seek out D. wrightii as an oviposition resource, females were predicted to feed upon it more than would males, which should be free to choose the best nectar resource. Using naive laboratory-reared moths in flight arena experiments, we found that both sexes preferred Datura wrightii over Agave palmeri (Agavaceae). Exposure to only one species and an odourless paper control, however, revealed sex-specific differences in foraging behaviour, with females feeding longer from A. palmeri and males feeding longer from D. wrightii, leading us to reject our hypothesis. Differences in feeding preferences directly translated into differences in energy intake. Females gained significantly more energy than did males by feeding from A. palmeri. We also examined whether behavioural preferences of moths in the laboratory translated into foraging behaviour in the field. Pollen load analysis of moths caught in 2004 showed that females carried significantly more A. palmeri pollen than did males, whereas males carried more D. wrightii pollen than did females. Whereas most studies examine pollination associations at the species level, our results highlight the potential importance of between-sex variation in floral visits.

Identification of Factors Influencing Flight Performance of Field-Collected and Laboratory-Reared, Overwintered, and Nonoverwintered Cactus Moths Fed with Field-Collected Host Plants

Environmental conditions during egg and larval development may influence the dispersal ability of insect pests, thus requiring seasonal adjustment of control strategies. We studied the longest single flight, total distance flown, and the number of flights initiated by wild Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae) to determine whether the flight performance of overwintered cactus moths with a prolonged feeding phase during development differs from nonoverwintered cactus moths. Pupae of field-collected and laboratory-reared moths were transported together from the United States to Switzerland, and flight mills were used to characterize the flight capacity of 24- to 48-h-old adults during their most active period of the diel cycle. The lack of seasonal variation in flight performance of those moths that developed under controlled environment but were fed with field-collected Opuntia cacti showed that seasonal changes in host plant quality did not affect flight. This consistent flight performance in the mass-reared laboratory population throughout the year is beneficial for sterile insect technique programs, which aim to limit the dispersal of this pest. For field-collected C. cactorum, the larger overwintered females performed similarly to nonoverwintered females, indicating that longer feeding time at lower temperature increases body size but does not influence female flight capacity. Young mated females had a similar flight capacity to unmated ones, suggesting that gravid females may play an important role in invading new habitats. For males, overwintering increased the proportion of long-distance flyers, suggesting that they are well-adapted to locate the more sparsely dispersed females in the spring.

Identification of Factors Influencing Flight Performance of Field-Collected and Laboratory-Reared, Overwintered, and Nonoverwintered Cactus Moths Fed with Field-Collected Host Plants

Environmental conditions during egg and larval development may influence the dispersal ability of insect pests, thus requiring seasonal adjustment of control strategies. We studied the longest single flight, total distance flown, and the number of flights initiated by wild Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae) to determine whether the flight performance of overwintered cactus moths with a prolonged feeding phase during development differs from nonoverwintered cactus moths. Pupae of field-collected and laboratory-reared moths were transported together from the United States to Switzerland, and flight mills were used to characterize the flight capacity of 24- to 48-h-old adults during their most active period of the diel cycle. The lack of seasonal variation in flight performance of those moths that developed under controlled environment but were fed with field-collected Opuntia cacti showed that seasonal changes in host plant quality did not affect flight. This consistent flight performance in the mass-reared laboratory population throughout the year is beneficial for sterile insect technique programs, which aim to limit the dispersal of this pest. For field-collected C. cactorum, the larger overwintered females performed similarly to nonoverwintered females, indicating that longer feeding time at lower temperature increases body size but does not influence female flight capacity. Young mated females had a similar flight capacity to unmated ones, suggesting that gravid females may play an important role in invading new habitats. For males, overwintering increased the proportion of long-distance flyers, suggesting that they are well-adapted to locate the more sparsely dispersed females in the spring.

Effect of learning on the oviposition preference of field-collected and laboratory-reared Chilo partellus (Lepidoptera: Crambidae) populations

Recent studies show that Vetiver grass, (Vetiveria zizanioides (L.) Nash), may have potential as a dead-end trap crop in an overall habitat management strategy for the spotted stem borer, Chilo partellus (Swinhoe) (Lepidoptera: Crambidae). Vetiver grass is highly preferred for oviposition, in spite of the fact that larval survival is extremely low on this grass. The oviposition behaviour of female Chilo partellus moths was investigated by determining the amount and size of egg batches allocated to maize and Vetiver plants and studying the effect of rearing conditions and oviposition experience on host plant selection. Two-choice preference tests were used to examine the effect of experience of maize (a suitable host plant) and Vetiver plants on the oviposition choice of C. partellus. For both field-collected and laboratory-reared moths, no significant differences were found in the preference distributions between the experienced groups. It is concluded that females do not learn, i.e. that they do not change their preference for Vetiver grass after having experienced oviposition on either maize or this grass, which supports the idea that trap cropping could have potential as a control method for C. partellus. Differences observed between field-collected and laboratory-reared moths in the amount and size of egg batches laid on maize and Vetiver grass indicate that data obtained from experiments with laboratory-reared insects should be treated with caution.

Synergy between visual and olfactory cues in nectar feeding by wild hawkmoths, Manduca sexta

We performed field experiments to measure the relative importance of olfactory and visual cues in nectar foraging by wild tobacco hornworm moths, Manduca sexta (Lepidoptera, Sphingidae) in the Sonoran Desert of Arizona, U.S.A. We manipulated flowers of sacred Datura (Datura wrightii; Solanaceae) to experimentally decouple floral scent from visual display and presented these cues to free-flying moths in mixed and homogeneous arrays. Moths did not feed from cloth-bagged fragrant flowers lacking strong visual contrast, nor did they feed from paper model flowers lacking plant odours. Unexpectedly, moths fed from paper model flowers that were associated solely with vegetative odours, albeit at lower levels than when floral scent was present. Subsequent experiments revealed that the combination of floral and vegetative odours did not incrementally increase nectar feeding and that floral scent without vegetation was sufficient to elicit feeding when paper flowers were present. Thus, wild M. sexta in our study did not show generalized feeding responses to natural or artificial flowers with single sensory stimuli; like naïve laboratory-reared moths, they required a combination of visual and olfactory cues. However, given the prior foraging experience of our study population on Datura flowers, their lack of generalized feeding responses may reflect a learned preference for the full complement of floral cues, rather than the persistence of innate sensory constraints. Future efforts to distinguish between these hypotheses should focus on whether M. sexta can be conditioned to associate nectar with visual cues alone, and whether moths that feed ad libitum from nectar-rich plants learn floral attributes as a search image or generalize to single-modality stimuli.

Transmission of Claviceps africana Spores from Diseased to Non-Infected Sorghum by Corn Earworm Moths, Helicoverpa zea

ABSTRACT The potential of corn earworm moths Helicoverpa zea, an important pest of sorghum in Texas, as a passive vector of sorghum ergot, Claviceps africana was assessed. Laboratory-reared (females and males) and field-moths trapped in sex pheromone traps were confined in screen cages with potted male-sterile sorghum line AT×623 that had been artificially infected with sorghum ergot and was producing massive amounts of honeydew that contained spores of the fungus. In the cages, moths were observed feeding on the honeydew. When laboratory-reared moths contaminated with C. africana spores were released for 12 or 48 h in cages containing healthy greenhouse- or field-grown male-sterile sorghum plants at anthesis, the levels of ergot severities on the panicles ranged from 0.5–90%, per panicle. The levels of ergot infection on greenhouse- and field-grown AT×623 exposed to ergot contaminated field-trapped males for 48 h ranged from 0–81.7%. Mean external contamination of laboratory-reared and field-trapped moths placed in a soapy wash was 1.4 × 105 and 4.7 ×104 conidia/ml, respectively. This study demonstrated that contaminated adult corn earworm could transmit the sorghum ergot from diseased to healthy panicles when environmental conditions are favorable for infection. Thus, migrating moths and other highly mobile pest species have the potential to transport C. africana over relatively large distances.

Effect of Synthetic Pheromone on Gypsy Moth (Lepidoptera: Lymantriidae) Trap Catch and Mating Success Beyond Treated Areas

Racemic disparlure sprayed at doses of 37 to 75 g/ha (AI) for mating disruption of gypsy moths, Lymantria dispar (L.), interfered with male moth search behavior outside of treated plots. Counts of feral male moths in pheromone-baited traps and the number of recaptured laboratory-reared moths gradually increased with increasing distance from treated areas. In most cases this effect was observed up to 250 m from treated plots. However, in one location it extended to 600 m along a narrow valley. The proportion of tethered females that mated during 1-d exposure increased gradually with increasing distance from treated plots. The relationship between male moth capture rates in pheromone traps and mating success of tethered females near treated plots was the same as the one observed in previous studies in pheromone-free areas.

Sapindus saponaria L. (Sapindaceae), a new host of Ecdytolopha aurantianum (Lima) (Lepidoptera: Tortricidae: Olethreutinae)

Ecdytolopha aurantianum (Lima) (Tortricidae: Olethreutinae) is a serious pest of citrus in Trinidad, West Indies. The forest tree Sapindus saponaria L. (Sapindaceae) is demonstrated to be an alternative host of E. aurantianum . S. saponaria flowers from November to December and fruit are suitable for the development of E. aurantianum from December to February. The total egg to adult development period in the laboratory at 25 C was 36.6+/-0.8 and 37.3+/-1.0 days for males and females respectively. Oviposition peaked 6 days after emergence. Variability in development rates, longevity of adults and fecundity was attributable partly to the degree of maturity of the host fruit. The mean fecundity was 86.9+/-8.5 eggs for moths reared in the laboratory and ranged from 13.6 to 58.3 for batches of moths collected as larvae in the field. Mean adult longevity of laboratory-reared moths was 9.5+/-0.4 and 10.0+/-0.4 days for males and females respectively, but was lower for adults reared from field-collected larvae. It is likely that other plant hosts, and/or a dormant phase, are important in the life history of the moth. Removal of S. saponaria adjacent to the citrus crop is recommended for control of the moth.

Oviposition Preferences of the Polyphagous Moth Choristoneura parallela (Lepidoptera: Tortricidae): Effects of Plant Species, Leaf Size, and Experimental Design

The fireworm Choristoneura parallela (Robinson) is a major pest of cranberry in New Jersey. Eggs typically are laid on the leaves of various weed species, and larvae disperse onto cranberry by ballooning. We used laboratory-reared moths and greenhouse experiments to investigate oviposition preferences among 3 weed species: greenbrier, Smilax rotundifolia L.; leatherleaf, Chamaedaphne calyculata (L.); and sheep laurel, Kalmia angustifolia L. In no-choice tests conducted in screen cages using cuttings, leatherleaf received the most egg masses whereas the other species did not differ. In this test there were no differences among species in the latency to the 1st egg mass; and the latency between the 1st and 2nd egg masses did not differ for greenbrier compared with the other species but was shorter for leatherleaf than for sheep laurel. The results were similar in 3-way choice tests conducted in screen cages using cuttings with leatherleaf receiving the highest percentage of egg masses and the other species not differing. However, a different preference hierarchy was found in 3-way choice tests conducted in plastic boxes using a single leaf of each species: greenbrier received the highest percentage of egg masses, leatherleaf received more than sheep laurel, and sheep laurel received no egg masses. Two-way choice tests using paired leaves in plastic boxes showed that larger greenbrier and leatherleaf leaves were preferred over smaller ones of the same species, but that leatherleaf was preferred over sheep laurel even when sheep laurel leaves were larger. These results demonstrate that this moth exhibits oviposition preferences among plant species but that the preference hierarchy depends on the experimental situation, and that both the species and the size of individual leaves can be factors.

Proboscis Extension Response of Adult Helicoverpa zea (Lepidoptera: Noctuidae) to Dry Sugars

Dry sugars were evaluated for their potential as feeding stimulants for the adult corn earworm, Helicoverpa zea (Boddie). The current study is part of an intensive effort to use adult feeding stimulants or attractants in programs to manage populations of H. zea on crops or on an areawide basis. Sucrose, fructose, glucose, and various other commercial sugarcane products (brown, powdered, and granulated sugars) along with raw sugar crystals were evaluated for their ability to elicit proboscis extension, a response essential for feeding, from laboratory-reared males and females and wild males captured in sex pheromone traps. We found that the particle size of sucrose was important in eliciting proboscis extension, and that ground sucrose and fructose were more stimulating than glucose. The most stimulating sugarcane product was powdered sugar and the response to it was similar to that found with ground sucrose and fructose. Laboratory-reared males and females were more responsive to small particles of sucrose, fructose, and powdered sugar than wild males captured in traps baited with sex pheromone. These results raise concerns about the use of laboratory-reared moths for assessing field adult feeding behavior. Although the low response of wild males to dry sugars raises some questions about the potential of these materials for use as feeding stimulants in management programs, more work is needed to gain a better understanding of the sensory mechanisms involved in the proboscis extension response to dry sugar particles and the conditions under which these particles elicit a feeding response.

Effect of an Ectoparasitic Nematode, Noctuidonema guyanense, on Adult Longevity and Egg Fertility in Spodoptera frugiperda (Lepidoptera: Noctuidae)

The effect of an ectoparasitic nematode, Noctuidonema guyanense Remillet & Silvain (Nematoda: Aphelenchoididae), on adult longevity and egg fertility in Spodoptera frugiperda (J. E. Smith) was studied in the laboratory. Infestation of S. frugiperda was achieved by crossing field-collected, infested moths with virgin, laboratory-reared moths. In 1989-1990, adult longevity of infested male moths was reduced by about 30%, whereas female longevity was reduced by about 15%. Longevity of female moths also was decreased by the nematode in 1991. Survival of field-collected moths was 63% less in infested moths than in noninfested moths 3 days after their confinement in the laboratory. Fecundity for infested and noninfested moths was similar in 1989-1990. However, in 1990, fertility was depressed in infested female moths by up to 20%. Among insects held under three constant temperature regimes (20, 25, and 30°C) in 1991, egg hatch was affected most at the lowest temperature. This is the first evidence of an ectoparasitic nematode affecting the biology of adult S. frugiperda .

Noctuidonema guyanense (Nematoda: Aphelenchoididae): Population Profiles on Male and Female Fall Armyworm Moths2

The distribution of Noctuidonema guyanense Remillet and Silvain (Nematoda: Aphelenchoididae) populations on wild female, laboratory-reared female, and wild male moths of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) was determined. Populations of all life stages of N. guyanense were aggregated (P < 0.05) on abdominal segments 7–10 of wild female and moderately infested (<100 nematodes), laboratory-reared female moths. Nematodes also aggregated on abdominal segments 7–10 on heavily infested (>300 nematodes), laboratory-reared female moths, but larger populations of all mobile life stages migrated from posterior to anterior abdominal segments of a host. On wild male moths, N. guyanense populations tended to disperse along the host's abdomen, with significant aggregates of eggs and neonates on abdominal segments 8–10 and smaller aggregates of adults and juveniles on abdominal segments 1–2. Nematodes avoided colonization of the head of nearly all hosts of either sex.

Larvicidal Actmty of 2 Pyrethroids from Different Spray Droplet Attributes, 1991

Abstract Asana-XL and Karate applied to cotton with 2 flat fan nozzles, Spraying Systems Co. 8002E and 650033, were evaluated for mortality of TBW larvae and fruit damage. The 2 nozzles, which were selected to give different spray droplet spectrums, also delivered different spray rates. AI rates used in the study were 0.0168 and 0.014 kg/ha for Asana-XL and Karate, respectively. These rates, which are half of the lowest recommended rate for each pyrethroid, were used in the study to better-detect treatment differences and because preliminary studies indicated extended persistence of these pyrethroids in the greenhouse. Plants were grown in the greenhouse, 2 plants/pot, to average heights of 0.5 m. A susceptible strain of laboratory-reared TBW moths deposited eggs on paper towel strips. These strips, with emerging larvae, were placed on untreated cotton plants, and larvae were allowed to feed for 2 days before being used in the tests. The 2 spray treatments were applied in a spray table to a series of plants for subsequent application of larvae on selected DAT. The treated plants were then returned to the greenhouse. Characteristics of the spray plumes from the 2 nozzles in the test sections where the plants were placed for treatment were:

Ovo-Larvicidal Efficacy of Aerially Applied Ovicides, 1990

Abstract Larvin, Ovasyn, and Curacron were applied aerially at 2 rates (0.14 and 0.28 kg (AI)/ha), 2 spray volumes (18.7 and 46.8 liters/ha), and 2 aircraft speeds (145 and 209 km/h). Cotton plants for the study were grown outdoors in 4 liter pots, 2 plants per pot, to an average height of 0.5 m. The test plants were transported to a staging area near the field where TBW eggs (0-24 h), collected from a susceptible strain of laboratory-reared moths, were transferred to selected cotton plants with a moistened brush. Nine eggs were placed on each of 3 fully-expanded terminal leaves of each plant in each pot prior to spraying (54 eggs/pot). The test plants were moved to the field and placed in rows of field-grown cotton plants of similar size. A Cessna Ag Husky was used to apply spray treatments. All test plants were then returned to the greenhouse for further treatment and evaluation. Eggs were also similarly placed on other sprayed plants 1 and 2 days after spraying. The 3 × 2 × 2 × 2 × 3 (ovicide × rate × spray vol × aircraft speed × days posttreatment) factorial arrangement of treatments was conducted in an experiment with 3 replications. Six days after egg placement, the plants were examined for egg hatch and larval mortality. The percentage eggs hatched and percentage larval recovery from hatched eggs were converted to percent mortality compared to an untreated check by Abbott's formula. Data were transformed by arcsine Vx prior to ANOVA.

Influence of Age and Season on Whole-Body Lipid Content of Plathypena scabra (Lepidoptera: Noctuidae)

Daily and seasonal changes in concentrations of whole-body lipids were examined in adult green cloverworms, Plathypena scabra (F.), to determine if seasonal trends were present. Laboratory-reared moths had a greater percentage of whole-body lipids overall compared with field-reared 5-d-old adults. Laboratory-reared males contained a significantly higher percentage of whole-body lipids than laboratory-reared females. Field-reared male adults contained a greater percentage of whole-body lipids during March, September, October, and November than those adult males reared in July and August. This may indicate a preparation for diapause or migration. Field-reared females showed no temporal differences in whole-body lipids. Inability to detect differences in females may be related to reproductive status.

Pink Bollworm (Lepidoptera: Gelechiidae): Laboratory Studies on the Effect of Cotton Plant Material on Mating and Oviposition of Laboratory-Reared and Feral Moths

Percentages of mating and spermatophores per female of feral but not laboratory-reared pink boll worm, Pectinophora gossypiella (Saunders), moths were increased near cotton plant material. Oviposition of feral and laboratory-reared moths increased near cotton plant material. Laboratory-reared pairs tended to begin mating about 1 to 2 h earlier than feral moths. Time in copula ranged from 67 to 81 min and 67 to 79 min for laboratory-reared and feral moth pairs, respectively. Feral female moths laid a higher percentage (66%) of their eggs on the cotton plant material, whereas laboratory-reared females laid a higher percentage (90%) on paper towel oviposition substrates.