Egg-laying Days Research Articles

Physiological and Biochemical Responses to Sublethal Concentrations of the Novel Pyropene Insecticide, Afidopyropen, in Whitefly Bemisia tabaci MED (Q Biotype)

Bemisia tabaci is a devastating agricultural insect pest worldwide, and B. tabaci MED (formerly biotype ‘Q’) threatens the production of horticultural and economic crops in China as a growing number of cases of insecticide resistance have issued, highlighting the requirement for alternative methods and measures of pest management. In the present work, the toxicities of eight popular chemical agents, including the novel pyropene insecticide afidopyropen, on adults of B. tabaci MED were determined, and then physiological and biochemical responses to sublethal concentrations were confirmed. Among all tested chemical agents, afidopyropen exhibited the highest toxicity to adult whiteflies (LC50: 7.38 mg/L). The sublethal effects of afidopyropen were studied at two sublethal concentrations, LC10 (0.53 mg/L) and LC25 (1.84 mg/L), and LC25 treatment extended the duration of growth stages and reduced viabilities in the stages of nymphal, pseudopupae, and adults. The egg-laying days and eggs laid per female were also decreased significantly, as was hatchability in the LC25 treatment. Metabolic enzyme assays suggested that the sublethal effects of LC25 treatment could be ascribable to enhanced detoxification mediated by glutathione S-transferase. In summary, our findings indicate that afidopyropen can be used as a chemical agent for the management of B. tabaci MED whiteflies.

Malleefowl Leipoa ocellata breeding behaviour: Insights from citizen science camera surveillance

Observations on natural history are a useful but often overlooked branch of ecology. With the use of camera-traps, collection of data e.g. on breeding behaviour and success has never been easier, particularly when studying cryptic species. Additionally, camera-traps are well suited to citizen science because of their ease of operation and the ability to store and verify data. Malleefowl Leipoa ocellata breeding behaviour has previously been studied through direct observation or timelapse photography, resulting in small sample sizes and potentially biased observations. Using camera-trap data collected by citizen scientists, we examined the breeding behaviour of this species. We quantified the timing and duration of mound-tending activities at 20 mounds using camera surveillance for >30,000 hours (1250 days) over six breeding seasons. Time spent at the mound during five mound stages and visit frequencies by the male and female during each stage are reported. Femaleinvolvement at the mound was consistent, although males spent three times as long at the mound compared with females during egg-laying. On egg-laying days, females spent longer uncovering the mound, compared with covering the mound post egg-laying. Our findings confirm that both male and female Malleefowl spend a substantial amount of time constructing and maintaining their mound throughout the year and, most notably, that the female consistently participates in mound-tending.These insights are particularly valuable as our surveillance was over markedly longer time spans than previous studies that relied upon direct observation.

Localized expression and inhibition effect of miR-184 on blood digestion and oviposition in Haemaphysalis longicornis (Acari: Ixodidae)

BackgroundThe hard tick Haemaphysalis longicornis (Ixodidae) is widely distributed in East Asia, China, Australia and New Zealand. It can transmit many infectious pathogens, including the causative agents of human rickettsiosis, bovine theileriosis, bovine babesiosis and canine babesiosis. Therefore, a greater understanding of H. longicornis biology might aid in the development of more effective control measures against the tick and tick-borne pathogens.MethodsWe analyzed the expression of miR-184 in different developmental stages and various tissues of H. longicornis using real-time PCR (qRT-PCR). Antagomir (Ant-184) was used to knock-down miR-184, whilst Ms-Ant and non-injected ticks were used as the negative and blank controls, respectively. We used online software tools (RNAhybrid and TargetScan) to predict the putative target genes of miR-184.ResultsThe expression of miR-184 was highest in unfed nymphs and lowest in unfed larvae. The tissue distribution of miR-184 showed abundant expression in the midgut. To investigate the probable roles of miR-184, antagomir (Ant-184) was used to knock-down miR-184 (t(4) = 12.32, P = 0.0002). After inhibiting miR-184, other biological factors were examined in each group. The engorged body weight was significantly reduced in the treated group (Ant-184) in contrast to control groups (t(22) = 2.19, P = 0.0388). The mean duration of the egg-laying days was significantly increased (33.5 ± 1.91) and the number of eggs (t(10) = 3.147, P = 0.0137), and egg mass (t(10) = 3.4472, P = 0.0063) were significantly reduced in the treated group. During oviposition, eggs were monitored and in half of the ticks of the Ant-184 group the eggs were completely desiccated, lacked embryo development and did not hatch. We analyzed the expression of Vg proteins (Vg1, Vg2, Vg3) in semi-engorged ticks, engorged ticks, ticks at day 2 after engorgement and egg stage in Ant-184, non-injected and Ms-Ant groups, and found significant variation.ConclusionsThis study provides information on the role of miR-184 in H. longicornis ticks. The data suggest that miR-184 targets Vg proteins and affects blood digestion and oviposition.

작은뾰족민달팽이(Deroceras reticulatum)의 발육과 수명에 미치는 온도효과

<TEX>$24^{\circ}C$</TEX>에서 작은뾰족민달팽이의 알 크기 (단경<TEX>$\times$</TEX>장경)는 <TEX>$1.91{\times}2.19$</TEX> mm, 무게는 3.3 mg 이었다. 산란 직후의 알에서부터 발육하여 우화한 성체가 최초 산란 시까지 17주간의 무게는 발육일수가 경과할수록 증가하였으며, 온도별 무게는 <TEX>$20^{\circ}C$</TEX>에서 가장 무거웠으며, 다음은 24, 16 및 <TEX>$28^{\circ}C$</TEX> 순이었다. 작은뾰족민달팽이가 산란한 난괴수의 부화율은 <TEX>$20^{\circ}C$</TEX>에서 95%로 가장 높았으며, 다음은 24, 16 및 <TEX>$28^{\circ}C$</TEX>의 순으로 유의한 차이가 있었다. 난괴당 알수는 <TEX>$20^{\circ}C$</TEX>에서 20개로 가장 많았으며 <TEX>$28^{\circ}C$</TEX>에서 10개로 가장 적었다. 누적 산란 일수는 <TEX>$20^{\circ}C$</TEX>에서 15일로 가장 길었으며, <TEX>$24^{\circ}C$</TEX>에서 9일로 가장 짧았고, 산란기간은 84~134일로 <TEX>$16^{\circ}C$</TEX>에서 가장 짧았으며, <TEX>$20^{\circ}C$</TEX>에서 가장 길었다. 그리하여 총 산란수는 <TEX>$20^{\circ}C$</TEX>에서 217개로 가장 많았고, <TEX>$16^{\circ}C$</TEX>에서 105개로 가장 적었다. 작은뾰족민달팽이의 알기간은 12~19일, 유체기간은 51~68일, 성체수명은 85~134일 이었으며, 알에서부터 성체수명까지의 총 생존기간은 <TEX>$20^{\circ}C$</TEX>에서 216일로 가장 길었으며, 다음은 <TEX>$24^{\circ}C$</TEX>에서 193일, <TEX>$16^{\circ}C$</TEX>에서 170일 및 <TEX>$28^{\circ}C$</TEX>에서 151일 순 이었다. 따라서 작은뾰족민달팽이의 산란, 발육 및 성체수명에 가장 유리한 온도는 <TEX>$20^{\circ}C$</TEX>로 여겨졌다. The egg size and weight of the gray field slug, Deroceras reticulatum Muller, was <TEX>$1.91{\times}2.19$</TEX> mm and 3.3 mg at <TEX>$24^{\circ}C$</TEX>, respectively. Its weight increased from newly laid eggs to adults for 17 weeks at four temperature regimes and was heaviest at <TEX>$20^{\circ}C$</TEX>, followed by 24, 16 and <TEX>$28^{\circ}C$</TEX>. Likewise, hatching rate of the egg batches was highest with 95% at <TEX>$20^{\circ}C$</TEX>, followed by 24, 16 and <TEX>$28^{\circ}C$</TEX> with significant differences. The number of eggs in the batches was increased with 20 at <TEX>$20^{\circ}C$</TEX> while it was only 10 at <TEX>$28^{\circ}C$</TEX>. The average accumulated egg-laying days was longest with 15 days at <TEX>$20^{\circ}C$</TEX> while shortest with 9 days at <TEX>$24^{\circ}C$</TEX>. The range of egg-laying period was shortest with 84-134 days at <TEX>$16^{\circ}C$</TEX> and longest at <TEX>$20^{\circ}C$</TEX>. Thus, the total number of eggs laid by adult D. reticulatum was highest with 217 at <TEX>$20^{\circ}C$</TEX> and lowest with 105 at <TEX>$16^{\circ}C$</TEX>. The egg period was 12-19 days while the juvenile period and adult longevity were 51-68 days and 85-134 days, respectively. The life span of D. reticulatum from egg to adult was longest with 216 days at <TEX>$20^{\circ}C$</TEX>, followed by 193 days at <TEX>$24^{\circ}C$</TEX>, 170 days at <TEX>$16^{\circ}C$</TEX> and 151 days at <TEX>$28^{\circ}C$</TEX>. Accordingly, the most favorable temperature for the oviposition, development and longevity of D. reticulatum is <TEX>$20^{\circ}C$</TEX>.

Egg Laying, Egg Temperature, Attentiveness, and Incubation in the Western Bluebird

We present the first detailed information on egg laying, egg temperature (Tegg), and development of attentiveness and incubation in Western Bluebirds (Sialia mexicana). We used miniature infrared CCD video cameras to record egg laying at three nest boxes and validate attentiveness measurements derived from Tegg in seven other nests. Females entered the nest box on egg-laying days between 0522 and 1037 hrs PST and laid an egg on average 11.4 6 4.3 min later (n 5 11). Warm weather early in egg laying often elevated Tegg above physiological zero (27u C), despite low parental attendance. Females often began roosting in the nest box 2-3 nights before clutch completion, and most birds began steady night-time incubation with the penultimate egg. Attentiveness, mean Tegg, and number of minutes Tegg exceeded 27u C reached their highest values 1 day or night after clutch completion. Western Bluebirds exhibit gradual onset to incubation that is attributable to vagaries of weather and varying patterns of parental attentiveness. Received 8 September 2008. Accepted 10 February 2009.

BREEDING BIOLOGY OF THE CHIPPING SPARROW IN PONDEROSA PINE FORESTS OF THE COLORADO FRONT RANGE

Abstract We present information on the breeding biology and nest-site characteristics of the western subspecies of the Chipping Sparrow (Spizella passerina arizonae) in montane ponderosa pine (Pinus ponderosa) forests of the Colorado Front Range. We located 83 nests during the summers of 1999–2002. The earliest egg date was 23 May and young fledged as late as 11 August. Nests were typically placed in needle clusters on outer branches of ponderosa pines. Mean canopy cover at nest sites was 50%. We observed no differences in nest placement or nest-site microhabitat between successful and unsuccessful nests. The nesting cycle lasted approximately 30 days, including 4 nest-building days, 3 egg-laying days, 14 incubation days, and 9 brooding days. Nests with known outcomes fledged a mean of 1.67 young from a mean clutch of 3.08 eggs. At least 27 nests (32.5%) were depredated, making predation the primary cause of nest failure. Of 42 successful nests, 5 (11.9%) were parasitized, although at least two Chipping S...

Feed Consumption Pattern of Laying Hens in Relation to Time of Oviposition

A total of sixty 67 week-old Manina White strain laying hens were individually housed in cages to investigate feed consumption pattern during the day in relation to time of oviposition. Hourly feed intake and time of oviposition were recorded for each bird for seven days. Mean hourly feed intake of all hens showed a smaller peak at 10:00-12:00 and a larger peak at 17:00-19:00. There were no significant differences in amount of daily feed consumption and hourly eating pattern between egg-laying days and non-laying days. However, hens consumed about 10 g more feed (p<0.01) on egg-forming days (the day before oviposition) than on non-egg- forming days. Hourly feed intake decreased prior to oviposition, but increased immediately during the time of oviposition. The peak consumption during the evening hours (17:00-19:00) was consistent regardless of the time of oviposition. (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 3 : 371-373)

An experimental study of mating competition in monogamous and polyandrous dunnocks, Prunella modularis: II. Influence of removal and replacement experiments on mating systems

‘Remove and release’ experiments were performed on 72 male dunnocks to investigate defence of mating opportunities, defence of territories, and factors influencing male status. Males were removed for 2–9 days, at various stages of the mating and incubation periods; all settled back on their territories when released. Territory size of males and females was unaffected by removals. When alpha (dominant) males were removed from trios, beta (subordinate) males successfully defended the territory alone and obtained significantly more mating access to fertile females, with no increase in the access of neighbouring males. By contrast, removal of monogamous males resulted in a significant increase in the mating access of neighbouring males and also led to changes in the mating system in 38% of cases. It is concluded that (1) polyandry does not arise because two males are necessary for successful defence of the territory against neighbours, and (2) mate guarding by alpha and monogamous males is necessary for maintaining exclusive mating access to females. In trios, removed alpha males were more likely to lose status when released if they had not previously obtained exclusive access to females during egg-laying days. Mating access (and hence brood value) was therefore an important asymmetry determining male dominance, supporting the ‘value asymmetry’ hypothesis for dominance. In monogamous pairs, removed males were again more likely to lose status and sole control of a territory if they had not previously obtained exclusive access to females on egg-laying days, but there was also strong support for the ‘resource-holding potential’ hypothesis because young newcomers were more casily usurped than were old newcomers.

Copulation behaviour of the tree swallow, Tachycineta bicolor: paternity assurance in the presence of sperm competition

Tree swallows engage in extra-pair copulations, creating an opportunity for sperm competition. The aim of this study was to determine whether the pattern of within-pair copulation was consistent with the use of frequent copulation by the male to assure paternity. Tree swallows attempted copulation frequently (65 times per clutch), 78% of which resulted in cloacal contact. Copulations were most frequent from 8 days prior to egg laying until early in egg laying. Over the whole season, pairs averaged (± se) 0·53±0·09 copulations/h in the morning and 0·22±0·05 copulations/h in the afternoon ( N=17 pairs). Early in the breeding season (prior to the egg-laying period), copulations occurred most often in the early morning. During the laying period, eggs were laid in the early morning and copulations occurred more often in the afternoon/evening. Females perched less often (and were therefore less available for copulation) during egg-laying days than directly before. Pairs spent less time together during egg laying than directly before egg laying. There was a trend towards higher copulation attempt rates under denser nesting conditions. Evidence supports the idea that males are attempting to protect their paternity by frequent copulation. The results also suggest that females dictate to some extent when copulations occur such that males do not necessarily copulate at times that are optimal for assuring paternity.

Factors Influencing Estimates of Sperm Competition in Rhagoletis pomonella (Walsh) (Diptera: Tephritidae)

In apple maggot fly, Rhagoletis pomonella (Walsh), using females that had mated twice, we investigated the occurrence of sperm predominance by using electrophoresis to analyze four enzymes (allozymes) of parents and offspring. A maximum likelihood method was used to estimate paternity when males did not differ unambiguously at any of the four loci. We found predominance of second male sperm in most cases; 79–93% of offspring were fathered by the second male. The degree of sperm predominance was not significantly affected by male mating treatment, number of days of female egglaying, or method of paternity determination (estimated or exact).

Egg Characteristics of High Performance Hens at the End of Lay When Given Cafeteria Access to Energy, Protein, and Calcium

Hens in excess of 90% egg production were selected from a flock at 67 weeks of age. All birds were fed a complete mash (18% protein, 2800 kcal metabolizable energy (ME)/kg, 3.75% Ca) for a 4-week standardization period. Two groups of 15 birds each were formed on the basis of equivalent production, egg weights, and body weights, One group continued to receive the complete feed for a subsequent 4-week experimental period, while the other group had free choice of a high energy mash (8% protein, 2800 kcal ME/kg, .75% Ca), a 50% protein pellet (2500 kcal ME/kg, .20% Ca), and oyster shell flakes. During the last week of each period, consumptions were determined at 2-hr intervals and eggs evaluated for quality, yield of physical components, and albumen electrophoretic distribution.No differences in production or in egg and body weights occurred because of feeding regimen. Hens, receiving the complete mash feed, consumed more ME, protein, and calcium on egg-laying days, but they utilized proportionately less of each than if these nutrients were cafeteria fed. Cafeteria access led to the consumption of protein early in the day while calcium was consumed later. Resultant eggs had an improved shell strength and an increased inner thin albumen at the expense of thick albumen. Protein concentration of outer thin, thick, and inner thin albumens remained constant, but constituent ovalbumin A1 increased while conalbumin, ovalbumins A2, and A3 decreased. Given the opportunity, hens consume nutrients parallel to their needs for egg formation, and in turn, improve shell and albumen yield.

Adult emergence and egg production of the black vine weevil in Canterbury

Abstract Adult emergence of black vine weevil, Otiorhynchus sulcatus (F.), from strawbenies (cv. ‘Tioga’) at Lincoln College, Canterbury occurred predominantly within a 15-day period in 1974. Most adults emerged between 23 October and 7 November. No adults were observed to overwinter. Egg production was recorded for adults held in the laboratory and fed diets of white clover, strawberry, or blackcurrant foliage. Egg production from the berryfruit-fed adults was significantly greater than that from clover-fed adults. Oviposition continued with all diets for more than 28 weeks, recordings being terminated at that point because of lack of foliage for feeding. Some adults survived for over a year. Oviposition records showed a cyclic pattern, mean number of egg-laying days per cycle being 51.1 and 49.2 for strawberry and blackcurrant respectively, and 12.2 for clover. The number of days between cycles was not significantly different between diets.

Factors Determining Variation in Fecundity of the Light Brown Apple Moth, Epiphyas Postvittana (Walker) (Tortricidae).

The large variation in fecundity in E. postvittana was associated with temperature, larval food plant, time of year each food plant occurs, and low-density larval crowding through mutual interference. Under field conditions, moths from larvae fed on curled dock, apple, plantain, white clover and capeweed laid &gt; 50% of their eggs by 5-7 days old and &gt; 80% by 8-12 days old. Cool conditions produced heavier individuals which lived longer and laid more eggs over an extended laying period. The fecundity and size (pupal weight) were probably influenced by the larval food plant and the time of year of feeding, presumably through seasonal variations in nutritive quality. Low-density larval crowding, despite excess food, significantly reduced fecundity and pupal weight; it occurs under natural conditions of high population density. The combined effect of these factors was cyclic variations in fecundity and size; more fecund, heavier individuals occurred during the cool wet months (winter generation adults) and less fecund, lighter individuals during the warm dry months (summer generation adults); spring generation adults were generally intermediate. The fecundity of E. postvittana can be adequately predicted from the number of egg-laying days.

Life History of Geocoris punctipes (Hemiptera: Lygaeidae) in the Laboratory1

At 25.5°±1.7°C, about 50% RH, and with 14 hr light per day, the average durations of the life stages of Geocoris punctipes (Say) were: egg, 9.9 days, both sexes; total nymphal, ♂26.8, ♀27.7 days; adults, ♂41.5, ♀67.7 days. Females averaged 5.2 days preoviposition and 30.8 egg-laying days, and produced 177.7 eggs per female (maximum 469) at an average rate of 5.5 eggs per clay.

A Laboratory Life History of the Consperse Stink Bug, Euschistus conspersus (Hemiptera: Pentatomidae)

The life history of Euschistus conspersus Uhler was studied in a laboratory maintained at 80°±2°F and 45%±5% RH, illuminated 15 hours per day. Bean pods served as food and paper toweling was utilized for egg deposition. Nymphs were reared individually in shell vials and 1-pint mason jars were used as cages for adults. Males and females did not differ significantly in the length of their developmental periods. Average durations of the several life stages were: egg 6.2 days; total nymphal period 25.6 days; adult male 128.2 days; adult female 75.1 days. The sex ratio was 49 females to 51 males. Females averaged 17.4 pre-oviposition days and 53.4 egg-laying days, and deposited an average of 225 eggs each (maximum 640 eggs). Oviposition and eclosion occurred throughout the 24-hour day, but most of the oviposition took place during the late afternoon and early evening hours.

Life History of Lygus hesperus (Hemiptera: Miridae) in the Laboratory

The life history of Lygus hesperus Knight was investigated in a laboratory maintained at 80° ± 2° F., with a 15-hour light day. Bean pods served as food and oviposition hosts. Shell vials were used as rearing cages in which bugs were confined individually. Average durations of the life stages were: egg, 7.1 clays for both sexes; total nymphal, males 13.2 days, females 13.8 days; adult, males 35.2 days, females 43.4 clays. The sex ratio was 113 males to 100 females. Females averaged 9.6 pre-oviposition and 32.2 egg-laying days, and deposited an average of 202.4 eggs per female (maximum, 448 eggs). Under the experimetal conditions oviposition and eclosion occurred throughout the 24-hour day.

Biological Studies of a Histiogaster Mite (Acarina: Acaridae) Associated with Pine Reproduction Weevils12

Of more than 40 species of wood-boring beetles checked, only the weevils Hylobius pales (Herbst) and Pachylobius picivorus (Germar) were found to have the mite Histiogaster anops Griffiths associated with them. The mite appears to be a normal inhabitant of the larval tunnels of the weevils, and apparently the adult weevils provide its only means of dispersal. The hypopus, the only stage found on the adult weevil, attaches to the weevil before it cuts through the bark to escape from its pupal chamber. The mites are easily reared with pine phloem or dry yeast as a food source. The feeding stages were consistently attracted more strongly to fresh as opposed to aged pine phloem, but were even more strongly attracted to fresh oak or catalpa phloems. Rearing experiments were successful only on oak and pine phloems. The mite requires an average of 9.6 ± 0.36 days from egg to adult when the hypopial stage does not occur. Average egg production was 101.5 eggs per female; one female produced 317 eggs in 17 egg-laying days. No parthenogenetic reproduction was observed.