Adult Emergence Patterns Research Articles

Influence of abiotic factors on seasonal and non-seasonal emergence of Tasar silkworm, Antheraea mylitta Drury

Aim: The present study was carried out to introspect the effect of temperature, humidity and rainfall on the emergence of Antheraea mylitta Drury. Methodology: An experiment on seasonal and non-seasonal emergence was carried out in 2019 and 2020 at Kathikund and Kharsawan of Jhakhand, India. Meteorological parameters (temperature, humidity and rainfall) were noted twice daily. Similarly number of adult moths emerged were age-graded and segregated as male and female. They were counted twice in a day within the grainage buildings (preservatory of seed cocoons). Results: The emergence of Antheraea mylitta varied month wise following: June to September, March to May, and November to February. Although the emergence of male individuals was more compared to females, no significant difference was observed statistically. Further increase in rainfall (57%) – humidity (15%) triggered more non-seasonal emergence of females. A strong positive correlation between humidity and rainfall with the emergence of adult moths compared to temperature throughout the year across both the seasonal (June-October) and non-seasonal (November-May) months was observed. The erratic/non-seasonal emergence was strongly correlated with humidity (0.75) compared to rainfall (0.32) and temperature (0.19). Daily emergence differed significantly (p<0.01) between the seasonal and non-seasonal months. Interpretation: During seasonal months, the number of adult moths emerged remained almost constant; however in non-seasonal months, the pattern of adult emergence exhibited a non-linear interrupted by sudden intervals of zero emergence. The intervals corresponded significantly to the effect of humidity and rainfall (p<0.001), however, no significant effect of temperature (p>0.05) was observed. Key words: Abiotic factors, Antheraea mylitta, Seasonal emergence, Tasar silkworm

Trap nesting bees of genus Megachile and nesting biology of three species of subgenus Callomegachile (Hymenoptera; Megachilidae) from North India

Abstract Studies conducted on the fitness of types of trap nests for Megachile bees showed that six species, viz. Megachile (Callomegachile) cephalotes, Megachile (Callomegachile) disjuncta, Megachile (Pseudomegachile) lanata, Megachile (Callomegachile) relata, Megachile (Eutricharaea) studiosella and Megachile (Callomegachile) umbripennis nested in tunnels (5-10 mm diameter), provided in different forms (drilled tunnels in bee nesting posts and wooden logs, and hollowed tunnels in bamboo sticks and reed stems). Nesting biology studies for three callomegachid bees, M. cephalotes, M. disjuncta and M. umbripennis, revealed that they nest in tunnels of similar length (; ) and diameter (; ). The cell walls and cell partitions were significantly different among the three species. The M. cephalotes females used resin to build their brood cells leaving an empty space. Megachile disjuncta females constructed their brood cells without leaving any basal space using resin as well as other materials in different combinations. In M. umbripennis, we recognized two distinct types of nests. One, similar to those of the two other resin bees usually having cylindrical or tubiform brood cells, and a second having only oval cells scattered all over in the nesting tunnel. The structural details of their nests exhibited several common features but also showed intraspecific and interspecific variations. This study provides new information on nesting details for these bees including their nest structure, brood development and adult emergence pattern for two different generations, which would be valuable in understanding the ecology of the diverse group of Megachile bees.

A multi-year dormancy strategy in a cabbage beetle population in southeastern China.

The life cycle of the cabbage beetle Colaphellus bowringi in southeastern China is complex due to four options for adult development: summer diapause, winter diapause, prolonged diapsuse, and nondiapause. However, detailed information on the multi‐year emergence patterns of diapausing individuals in this beetle has not been documented. In this study, we monitored the adult emergence patterns of diapausing individuals and estimated the influence of the diapause‐inducing temperature and photoperiod on the incidence of prolonged diapause under seminatural conditions for several years. The duration of diapause for adults collected from the vegetable fields in different years varied from several months to 5 years. Approximately 25.9%–29.2% of individuals showed prolonged diapause (emergence more than 1 year after entering diapause) over the 5 years of observation. Furthermore, regardless of insect age, the emergence of diapausing adults from the soil always occurred between mid‐February and March in spring and between late August and mid‐October in autumn, when the host plants were available. The influence of diapause‐inducing temperatures (22, 25, and 28°C) combined with different photoperiods (L:D 12:12 h and L:D 14:10 h) on diapause duration was tested under seminatural conditions. Pairwise comparisons of diapause duration performed by the log‐rank test revealed that the low temperature of 22°C combined with the long photoperiod of L:D 14:10 h induced the longest diapause duration, whereas the low temperature of 22°C combined with the short photoperiod of L:D 12:12 h induced the highest proportion of prolonged diapause. This study indicates that C. bowringi adopts a multi‐year dormancy strategy to survive local environmental conditions and unpredictable risks.

Temporal and age-related variations in calling and mating patterns of the Indian population of spotted pod borer, Maruca vitrata Fabricius (Lepidoptera: Crambidae)

Maruca vitrata is an important pantropical and polyphagous insect pest of grain legumes. The adult emergence pattern and temporal variations in the calling and mating behaviour of M. vitrata across ages were studied. Observations revealed that adult emergence was not influenced significantly by sex, but by the time of the day. Calling activity is a strong determinant of male mating success in insects. An age-dependent female calling pattern was observed. Females seldom called on their day of emergence, calling percentage was low to nil in the first four hours of scotophase but reached a peak in the fifth hour. The calling patterns of females of different ages were similar except that there were two peaks of calling for 3 and 4 days old females. Like calling, the mating pattern was also age-dependent, i.e. M. vitrata mating frequency was maximum at 3-days of age and thereafter decreased gradually with age. The highest mating frequency (30.83%) was observed at 2200 h for 3-day-old moths. The current study revealed that age dependant and distinct patterns in female calling, synchronous male responsiveness leading to mating in M. vitrata. The output of the study could be utilized in various aspects of M. vitrata semiochemical based research.

Simulated climate change, but not predation risk, accelerates Aedes aegypti emergence in a microcosm experiment in western Amazonia.

Climate change affects individual life-history characteristics and species interactions, including predator-prey interactions. While effects of warming on Aedes aegypti adults are well known, clarity the interactive effects of climate change (temperature and CO2 concentration) and predation risk on the larval stage remains unexplored. In this study, we performed a microcosm experiment simulating temperature and CO2 changes in Manaus, Amazonas, Brazil, for the year 2100. Simulated climate change scenarios (SCCS) were in accordance with the Fourth Assessment Report of Intergovernmental Panel on Climate Change (IPCC). Used SCCS were: Control (real-time current conditions in Manaus: average temperature is ~25.76°C ± 0.71°C and ~477.26 ± 9.38 parts per million by volume (ppmv) CO2); Light: increase of ~1,7°C and ~218 ppmv CO2; Intermediate: increase of ~2.4°C and ~446 ppmv CO2; and Extreme: increase of ~4.5°C and ~861 ppmv CO2, all increases were relative to a Control SCCS. Light, Intermediate and Extreme SCCS reproduced, respectively, the B1, A1B, and A2 climatic scenarios predicted by IPCC (2007). We analyzed Aedes aegypti larval survivorship and adult emergence pattern with a factorial design combining predation risk (control and predator presence-Toxorhynchites haemorrhoidalis larvae) and SCCS. Neither SCCS nor predation risk affected Aedes aegypti larval survivorship, but adult emergence pattern was affected by SCCS. Accordingly, our results did not indicate interactive effects of SCCS and predation risk on larval survivorship and emergence pattern of Aedes aegypti reared in SCCS in western Amazonia. Aedes aegypti is resistant to SCCS conditions tested, mainly due to high larval survivorship, even under Extreme SCCS, and warmer scenarios increase adult Aedes aegypti emergence. Considering that Aedes aegypti is a health problem in western Amazonia, an implication of our findings is that the use of predation cues as biocontrol strategies will not provide a viable means of controlling the accelerated adult emergence expected under the IPCC climatic scenarios.

Adult emergence patterns and body size of two mayfly species of Isonychia Eaton, 1871 from Hokkaido, Japan

We conducted an emergence survey of Isonychia (Isonychia) japonica Ulmer, 1919 and Isonychia (Prionoides) shima Matsumura, 1931 at four sites in the Izari-gawa River system, Hokkaido, Japan in 2015 and 2016 to investigate differences in emergence seasons between the species. The present study showed that I. (I.) japonica was widely distributed from up- to down-stream with abundant numbers in middle-stream, while I. (P.) shima was mostly distributed up-stream. The emergence season of I. (I.) japonica was longer than that of I. (P.) shima, but their emergence periods overlapped in August and early September, suggesting that their adults are not separated temporally. Body size comparison showed that, at the same sites, the emerged in August specimens of I. (I.) japonica were larger than those of I. (P.) shima.

WITHDRAWN

The document associated with this DOI has been withdrawn.

The reproductive behavior and evaluation of sex pheromone gland extracts of Ectropis grisescens (Lepidoptera: Geometridae)

The geometrid, Ectropis grisescens Warren, is one of the most serious defoliators of the green tea, Camellia sinensis. In the present study, adult emergence, calling behavior, mating activities, and oviposition patterns were observed and the effect of female sex pheromone was evaluated under laboratory conditions (25 ± 1 °C, 14:10 light/dark and 70–75% RH). Adult emergence and calling behavior occurred only at the scotophase. The peak emergence occurred 2 h into the scotophase for males and 3 h for females. Female calling behavior occurred during 1–4 days after eclosion, with most callings among the 1-day-old and the calling gradually decreasing by the age. Mating behavior was first observed at the 2 h into the scotophase. While the mating peak time was similar, 6–8 h into the scotophase for single-pair and multiple-pair groups, the peak of oviposition was 3 days after mating. The pheromone gland extracts from the abdominal tips of 1–2 days virgin female moths were more attractive than the virgin females or the control in the wind tunnel tests. Our findings provide scientific basis to ecological control of E. grisescens.

Irrigation and Grass Cover Effects on Pupal Survival Rates in Soil and Adult Emergence Patterns of Rhagoletis indifferens (Diptera: Tephritidae).

Western cherry fruit fly, Rhagoletis indifferens (Curran; Diptera: Tephritidae), occurs in unmanaged cherries (Prunus spp.) across dry climates in Washington State and other regions in western United States and Canada. To help explain the fly's distribution in arid climates, we determined the effects of adding water to bare and grass-covered soils on pupal survival rates and adult emergence patterns of R. indifferens in central Washington. Water was added ('irrigated') or not to bare soil and grass-covered soil in cylinders pressed into the ground. Larvae were added to cylinders and pupal survival and adult fly emergence determined over three seasons. Irrigating bare soil had no effect on pupal survival or adult emergence, but in grass-covered soil, irrigation increased pupal survival (15.2-17.0% vs 6.7-9.5%) and adult emergence (2 of 3 yr, 12.8 and 24.1 vs 1.1 and 11.6%; no difference in 1 yr). Pupal survival was greater in bare (24.5-47.7%) than grass-covered soil (6.7-17.0%). Moisture was higher in irrigated than unirrigated treatments but within irrigated treatments, moisture in bare versus grass-covered soil did not differ. In both irrigated and unirrigated treatments, humidity in soil 5 cm below the surface where many pupae reside was >60%, including during summers. Results suggest R. indifferens pupae tolerate unirrigated soils during summer because soil moisture and high humidity there can prevent desiccation, contributing to the fly's wide distribution and abundance in dry climates, and that dry, grass-covered soils or mulch barriers in mid- and late-summer could reduce fly survival under some conditions.

Forecasting Spring Emergence of the Asian Corn Borer, Ostrinia furnacalis (Lepidoptera: Crambidae), Based on Postdiapause Development Rate.

This study was conducted to develop temperature-dependent postdiapause development models of overwintering larvae of the Asian corn borer, Ostrinia furnacalis Guenée (Lepidoptera: Crambidae), and to evaluate the models' forecasting accuracy using spring adult emergence data. Overwintering larvae were collected at three different times: 24 February (first), 23 March (second), and 25 April (third), 2005. The developmental periods of each collection colony were measured at eight constant temperatures, and those developmental rates were modeled with linear and nonlinear regression. One linear and three nonlinear models provided good fits of developmental rate to temperature across all colonies (r2 = 0.96-0.99). The distribution of development completion time was modeled with a Weibull equation that fit data from the second (r2 = 0.92) and third (r2 = 0.97) colonies better than the first (r2 = 0.87). A Lactin 2 model based on data from the first colony was statistically the best model to describe the relationship between temperature and the postdiapause development rate of O. furnacalis (r2adj = 0.99). However, validation results based on the field data showed that the Logan 6 model combined with the Weibull model (based on the second colony) was well describing spring adult emergence patterns up to 50% cumulative emergence date.

Pupal emergence pattern in cactophilic Drosophila and the effect of host plants.

Drosophila buzzatii and D. koepferae are sibling cactophilic species. The former breeds primarily on prickly pears (genus Opuntia) whereas the latter breeds on columnar cacti of the genera Cereus and Trichocereus, although with certain degree of niche overlapping. We examined the interspecific differences in diurnal temporal patterns of adult emergence from puparia and evaluated whether this behavior is affected by rearing in the different cactus hosts available in nature. We detected important host-dependent genetic variation for this trait differentially affecting the emergence schedule of these species. Diurnal pattern of emergence time was directly correlated with developmental time and negatively correlated with adult wing size, suggesting that early emergences are at least indirectly correlated with increased fitness. We discussed our results in terms of their putative effects on fitness and the genetic-metabolic pathways that would be presumably affected by host's nutritional-chemical differences.

Modeling adult emergence and fecundity of factitious hosts under different food sources supports massive egg production management.

Ephestia kuehniella (Lepidoptera, Pyralidae) and Sitotroga cerealella (Lepidoptera, Gelechiidae) are important factitious hosts used for production of biological control agents. Their differences in terms of biology and behavior require adjustments in their mass production, particularly when using corn or barley as food in grain or in bran. We modeled adult emergence, oviposition period and egg production along time after emergence, as a function of the food source. Significant differences between hosts or food type were found for these variables and for adult weight but not for sex ratio. Our results confirm the possibility of mass production of these hosts using corn or barley as food source. Integrating adult emergence patterns and age specific fecundity patterns into a single model, it is clear that rearing E. kuehniella on barley would result in the highest egg output in much shorter time than E. kuehniella on corn or S. cerealella on barley.

Central and peripheral clocks are coupled by a neuropeptide pathway in Drosophila

Animal circadian clocks consist of central and peripheral pacemakers, which are coordinated to produce daily rhythms in physiology and behaviour. Despite its importance for optimal performance and health, the mechanism of clock coordination is poorly understood. Here we dissect the pathway through which the circadian clock of Drosophila imposes daily rhythmicity to the pattern of adult emergence. Rhythmicity depends on the coupling between the brain clock and a peripheral clock in the prothoracic gland (PG), which produces the steroid hormone, ecdysone. Time information from the central clock is transmitted via the neuropeptide, sNPF, to non-clock neurons that produce the neuropeptide, PTTH. These secretory neurons then forward time information to the PG clock. We also show that the central clock exerts a dominant role on the peripheral clock. This use of two coupled clocks could serve as a paradigm to understand how daily steroid hormone rhythms are generated in animals.

Local adaptation, intrapopulation adult emergence patterns, sex and prolonged diapause regulate the rate of postwinter development in pupae of the European cherry fruit fly

Local adaptation, intrapopulation adult emergence patterns, sex and prolonged diapause regulate the rate of postwinter development in pupae of the European cherry fruit fly

Adult emergence pattern and utilization of females as attractants for trapping males of white grubs, Leucopholis lepidophora (Coleoptera: Scarabaeidae), infesting areca nut in India

White grub, Leucopholis lepidophora Blanchard (Coleoptera: Scarabaeidae: Melolonthinae), is a major insect pest infesting areca nut in India. Larvae feed on roots (hence also called root grubs), causing reduced number of roots, loss of anchorage, stem tapering, reduced number of fronds, yellowing of leaves, yield reduction and death of the plants. The biology and ecology aspect of this scarabaeid are scanty. Hence, the aim of this study was to understand the ecological and behavioral aspects to develop IPM program. The adult emergence pattern of L. lepidophora was observed daily during the rainy season. The emergence period was defined between June and October during 2013 and 2014. Peak emergence of adult beetles occurred between 1900 and 2000h. When raining occurred between 1800 and 2100h, no emergence of adult beetles was observed. The sex ratio of L. lepidophora varied over time, but the overall sex ratio was female biased in both the study years (female:male; 1:1.18 and 1:1.46 in 2013 and 2014, respectively). Males were found to emerge first in the season resulting in protandry. Innovative idea emerged during our field experiments in 2013–2014 was the use of female beetles for attracting male beetles. Female adults were collected and placed individually in traps made of small pouches of nylon net and were tied to the areca palm at a height of 5ft. Trap containing a female beetle attracted male individuals for about 8–10days. The same technique was employed for the large-scale collection of beetles during 2014. A total of 1843 males were collected in an areca grower's field using female-baited traps during 2014. Male baited traps did not attract female beetles, indicating existence of only female produced semiochemical that attracts males. Our findings provide new insights for incorporating adult collection using female-baited traps in IPM against areca nut white grubs.

Thermoperiodism Synchronizes Emergence in the Alfalfa Leafcutting Bee (Hymenoptera: Megachilidae).

Alfalfa seed production in the northwestern United States and western Canada is heavily dependent upon the pollinating services of Megachile rotundata (F.) (Hymenoptera: Megachilidae). M. rotundata females nest in cavities either naturally occurring or in artificial nesting blocks. Because of the physical nature of the nest, M. rotundata brood may have limited to no exposure to photoperiodic cues in order to regulate important circadian functions. Therefore, various thermoperiod regimes were used to characterize the possible role of thermoperiodism in synchronizing M. rotundata adult emergence. Adult emergence was monitored using a microprocessor-controlled event logger. Incubating bees under constant 29°C and darkness resulted in an arhythmic adult emergence pattern. Exposing developing M. rotundata to a thermoperiod synchronized emergence to the beginning of the thermophase and decreased the total number of days required for all adults to emerge. The amplitude of the thermoperiod regulated the timing of peak emergence in relationship to the increase in temperature. A thermoperiod amplitude of only 2°C was sufficient to synchronize peak adult emergence to take place during the rise in temperature. Increasing the amplitude of the thermoperiod to 4 or 8°C caused a positively correlated shift in peak emergence to later in the thermophase. Brood stored under constant 29°C and darkness for different durations (May or June early in the growing season or July or August late in the growing season) or under a fluctuating thermal regime (base temperature of 6°C and daily 1-h pulse of 20°C until September or November) maintained their capacity for entraining emergence timing by thermoperiodism.

Periodicity of adult emergence and sexual behaviour of coconut black headed caterpillar, Opisina arenosella Walker (Lepidoptera: Oecophoridae)

In Lepidoptera sexual, oviposition and adult emergence behaviour follows a specific periodicity and is limited to either the day or the night. The knowledge on biology and behaviour are prerequisites for semiochemical based pest management. The periodicity of adult emergence, calling, courtship, mating and oviposition behaviour of Opisina arenosella Walker (Lepidoptera: Oecophoridae) was studied under laboratory conditions. Results revealed that males emerged 3-7 days prior to female. Both males and females emerged during 1st to 7th h of scotophase. Peak emergence of male and female was recorded on 2nd and 3rd hrs, respectively. Calling of virgin females started 1-2 hrs after emergence and there is no sexual maturation time. The female calling starts at 4th h of the scotophase and end during 7th h but is slightly delayed for females who emerged the same night. While male wing fanning start from 3rd h of scotophase continued to 11th h. Peak mating occurred on 5th h of scotophase with mean mating duration of 58.83±0.804 min. Oviposition required 2 days maturation period. Peak oviposition occurred during 3rd and 4th scotophases. Oviposition by females started in early hours of scotophase and peaked at 6th h. The female fecundity was 273.63±64.01. Adult emergence, calling, mating and oviposition pattern of the moths showed periodicity occurring precise time of scotophase.

Effects of juvenile hormone analogue and ecdysteroid on adult eclosion of the fruit fly Bactrocera minax (Diptera: Tephritidae).

The univoltine Bactrocera minax (Enderlein) is a devastating pest of citrus in Nepal, India, Bhutan, and China. To better understand the overwintering pupal diapause, we investigated the juvenile hormone III (JH III) and ecdysteroid 20-hydroxyecdysone (20E) titers across the developmental stages, and the effects of juvenile hormone analog (JHA) and 20E treatments on adult emergence patterns. The results showed that both JH III and 20E levels fluctuated from the late larval stage to the late pupal stage. JHA and 20E treatments at the late larval stage had marginal effect on the adult emergence patterns, with slightly faster adult eclosion and higher eclosion rate. Similarly, JHA treatment at the early pupal stage did not affect the adult emergence. However, 20E treatment at the early pupal stage remarkably shortened the duration of diapause, but lowered the eclosion rate, especially with relatively high dose. These findings demonstrated that 20E treatment at the early pupal stage is a suitable method to hasten the diapause termination of B. minax, which will contribute to the rearing of B. minax in the laboratory as needed for routine experiments.

Differential Effects of 4-n-Nonylphenol on Glutathione, Glutathione S-Transferase, and Glutathione Peroxidase on Gonads in Different Developmental Stages in the Bombyx mori (Lepidoptera: Bombycidae)

Abstract Bombyx mori L. larvae were exposed to 4-n-nonylphenol (4-NP) in the laboratory, and their glutathione S-transferase, glutathione peroxidase, and corresponding mRNA levels in gonads during different developmental stages (larval, pupal, and adult) were evaluated. Developmental parameters and glutathione content were also measured. Altered patterns of pupation and adult emergence were observed after exposure to 0.05–0.4 g/kg 4-NP during the entire larval stage. When exposed to 0.4 g/kg 4-NP, the sex ratio (male/female) of the emerged adults increased rapidly from 0.91 ±0.09 to 1.96 ±0.26. A decrease in glutathione content was observed at the larval, pupal, and adult stages. In addition, at 0.05 g/kg 4-NP and higher concentrations, an increase in glutathione S-transferase, glutathione peroxidase activity, and the gene expression level of glutathione S-transferase d1 and glutathione peroxidase were detected in the larval stage, followed by a decline in glutathione S-transferase d1 and glutathione peroxidase transcript levels along with enzyme activity in the pupal and adult stages. The changing trend in mRNA levels of these enzymes was consistent with that of enzyme activity. The results suggest a relationship between 4-NP and alterations in the levels of glutathione-related detoxification enzymes in B. mori gonads.

Alternative Fumigants to Methyl Bromide for Killing Pupae and Preventing Emergence of Apple Maggot Fly (Diptera: Tephritidae)

Abstract Effects of methyl bromide, ECO2FUME (phosphine gas + CO2), Vapam (sodium methyldithiocarbamate), chloropicrin, Telone II (1, 3 dichloropropene), and chloropicrin + Telone II on killing the pupae and preventing adult emergence of apple maggot fly, Rhagoletis pomonella (Walsh), was determined. In an experiment performed inside glass flasks, pupal mortality caused by all fumigants 7 d after a 4-h exposure was significantly higher than in the control, but effects of the five fumigants on pupal mortality 7 d post exposure did not differ consistently even though chloropicrin caused the highest absolute mortality. In contrast, fumigant effects on adult emergence were consistent and clearer in that chloropicrin, Telone II, and chloropicrin + Telone II prevented all emergence of adult flies over 111 - 112 d whereas methyl bromide, ECO2FUME, and Vapam reduced it by only 41 - 73% compared with controls. The differences in pupal mortality and adult emergence patterns suggest that the fumigants acted slowly. ...