Time Of Egg-laying Research Articles

The Impact of Laying Hen Age, Egg-Laying Time, Cage Tier, and Cage Direction on Egg Quality Traits in Hens in an Enriched Cage System

The Impact of Laying Hen Age, Egg-Laying Time, Cage Tier, and Cage Direction on Egg Quality Traits in Hens in an Enriched Cage System

First record of geophagy in Jungle Babbler (Turdoides striata) prior to egg-laying: an instinct for calcium supplement.

Geophagy has been documented in different animal taxa including Aves and particularly in Passeriformes. However, no geophagic activity has been reported in the genus Turdoides of the family Leiothrichidae belonging to the passerine order. Studies reveal the behaviour of geophagy to be aiding in nutrient supplementation, toxin neutralisation, cytoprotection, gut pH stabilisation and parasite liberation. Here, we provide a record of geophagy in Jungle Babbler Turdoides striata in a peri-urban area of Berhampur city in India. Although this species, being insectivorous, was thought to be feeding on insects, nevertheless, close observations confirmed the activity to be a case of geophagy, which was followed up by nest-building, egg-laying and hatching. The soil samplesfrom the geophagic sites (Ca = 2415mg/kg) contained 130% more Ca than that of the non-geophagic sites (Ca = 1050mg/kg). The biochemical requirement of calcium throughout the reproductive phase of Turdoides sp. may corroborate the soil consumption instinct, which was also extrapolated from the reproductive success observed, because the demand for calcium in birds remains high during the egg-laying time. Although the possible explanations for geophagy, reported for the first time in this species, were oriented specifically towards Ca supplement, the present findings provide impetus for furthering research in this domain.

Effect of Hen Genotype and Laying Time on Egg Quality and Albumen Lysozyme Content and Activity.

According to research, egg quality and lysozyme content are influenced by a number of factors, which are mostly known in the case of commercial hybrids, while in breeds included in genetic resources conservation programmes, new research results in this regard are emerging. The aim of the study was to determine the effect of egg laying time and genotype of selected Polish native breeds of hens on egg quality and lysozyme content and activity in the albumen. The study material consisted of eggs collected from four strains of laying hens included in the Polish conservation programme, i.e., Green-legged Partridge (Z-11), Yellow-legged Partridge (Ż-33), Rhode Island Red (R-11) and Leghorn (H-22). At week 56, 28 eggs were randomly collected at 7:00 and 13:00 h from each breed of hen and assessed for quality. Laying time influenced certain egg quality traits. Eggs laid by hens in the morning were characterised by 1.7 g lower total weight and albumen weight, 2.4 pores/cm2 higher number of shell pores, 0.15 higher albumen pH values and 0.17 lower yolk pH values compared to those laid in the morning. The time of laying did not affect the level and activity of lysozyme in the albumen. A significant negative correlation was found between eggshell traits and albumen height, and between Haugh unit and lysozyme content and activity in the albumen. The studied egg quality traits were more influenced by genotype than by the egg-laying time.

Higher Essential Amino Acid and Crude Protein Contents in Pollen Accelerate the Oviposition and Colony Foundation of Bombus breviceps (Hymenoptera: Apidae)

Pollen is an important source of nutrition for bumblebees to survive, reproduce, and raise their offspring. To explore the nutritional requirements for the egg laying and hatching of queenright Bombus breviceps colonies, camellia pollen, oilseed rape pollen, apricot pollen, and mixtures of two or three types of pollen in equal proportions were used to feed the queens in this study. The results showed that the camellia pollen with a higher essential amino acid content was superior to the pollen with a lower essential amino acid content in the initial egg-laying time (p < 0.05), egg number (p < 0.05), larval ejection (p < 0.01), time of first worker emergence (p < 0.05), and the average weight of workers in the first batch (p < 0.01). It took less time for colonies under the camellia pollen and camellia-oilseed rape-apricot pollen mix treatments, both with a higher crude protein content, to reach ten workers in the colony (p < 0.01). On the contrary, the queens fed apricot pollen never laid an egg, and larvae fed oilseed rape pollen were all ejected-both pollens with a lower essential amino acid content. The results emphasize that the diet should be rationally allocated to meet the nutritional needs of local bumblebees at various stages when guiding them to lay eggs, hatch, and develop a colony.

Human tumor necrosis factor alpha affects the egg-laying dynamics and glucose metabolism of Schistosoma mansoni adult worms in vitro

Several studies have described the effects of human tumor necrosis factor alpha (hTNF-α) on Schistosoma mansoni. hTNF-α affects the worm’s development, metabolism, egg-laying, gene expression and protein phosphorylation. The available data on the influence of hTNF-α on egg-laying in S. mansoni are controversial, but understanding the mechanism of egg-laying regulation in this species is essential in combating schistosomiasis. We characterized the effects of in vitro treatment of S. mansoni adult worms with different doses of hTNF-α (5, 20 and 40 ng/ml) for 5 days. We explored the effects on egg-laying rate, glucose levels, ATP metabolism, and messenger RNA (mRNA) expression levels of lactate dehydrogenase, glucose transporters and the parasite gene which acts as an hTNF-α receptor, SmTNFR. hTNF-α influenced egg-laying in a time- and dose-dependent manner: at a dose of 40 ng/ml, egg-laying increased on day 2 and decreased on days 3 and 4; at 20 ng/ml, egg-laying decreased on day 3; while at 5 ng/ml, egg-laying decreased on day 4. The total number of eggs produced was not affected by the different treatments, but the egg-laying dynamics were: the median egg-laying time decreased significantly with treatment, and egg developmental stages and size were also affected. At 5 and 20 ng/ml hTNF-α, lactate production diminished on day 3 up to day 5, while glucose uptake increased on day 5. At 40 ng/ml, glucose uptake diminished on day 1 up to day 3, while ATP accumulation was detected on day 5. No significant changes in mRNA expression were detected in any of the treatments. We found that crosstalk involving hTNF-α and parasite signaling plays a role in the fine-scale regulation of the worm’s metabolism and physiology, and points to new strategies for disease control.Graphical abstract

Reduced oviposition period promotes blowfly population extinction in Nicholson’s model

ABSTRACT Blowflies use open wounds or the accumulation of feces or urine in wool to lay their eggs. The larvae that emerge cause lesions in the host sheep, which can lead to death. They are found in Australia, New Zealand, and the United Kingdom. Nicholson’s model describes the population dynamics of the Australian blowfly (Lucilia Cuprina). It incorporates environmental variation. The extinction of these flies depends on the time to oviposition and the time between generations. The Lyapunov function, which is positive with a negative derivative, provides the condition for the stability of the equilibrium point: the oviposition period must be sufficiently short, because the shorter it is, the more it favors the extinction of the species. The zero solution is the only equilibrium point, synonymous with the extinction of the population. Another species of blowfly, Lucilia Sericata, also attacks sheep in Australia. Both blowflies are ectoparasites of warm-blooded vertebrates, particularly domestic sheep. These two blowflies are related to share same mitochondrial DNA sequences, although the two species are distinct. Presumably to avoid competition between them. the egg-laying time of each species does not occur at the same time of year: L. Sericata prefers warmer months, thus in summer, while L. Cuprina is mainly active in autumn. Laying of eggs in different months allows avoiding competition between these species. This also binds them together. A sufficiently small egg-laying delay then leads to the rapid extinction of both blowfly populations, provided they do not adapt.

The Effects of Climate Change on Birds and Approaches to Response

Complex changes in climate change have caused numerous changes, such as rising temperature and increasing in precipitation frequency, representing dynamic environmental changes for birds. It results in birds’ responses, such as changes in migration routes. To better understand the responses, the study aims to reveal the impacts of climate change on birds’ behavior and proper approaches toward addressing its effects. The study shows that climate change has caused advanced spring migration, changes in birds’ habitat, higher possibility of disease transmission, earlier egg-laying time, less food availability, and a decline in the bird population. The study also lists possible measures to mitigate climate change’s influence, including environmental policies, partnership with non-government organizations, and decreasing greenhouse emissions. In the future, people should consider identifying knowledge gaps of the link between climate change birds from efforts of interdisciplinarity and multi-academic fields. The same approach also applies to plausible solutions exploration. The study provides a comprehensive summary of the effects of climate change on birds, as well as briefly illustrates the current approaches to mitigate its impacts. It increases the awareness of climate change’s impacts for the present generation, in turn encouraging them to take progressive actions to address the problem for the future generation.

Determination of colony characteristics and suitability for mass production of native Bombus terrestris L. population in the Central Black Sea coast region

In this study, two successive generations of queens belonging to a native Bombus terrestris population in the Central Black Sea Region of Türkiye were reared under controlled laboratory conditions to examine its developmental characteristics and suitability for mass production. The first generation was formed by a hundred Bombus terrestris queens which were caught from native fauna in Ordu Province, Türkiye. Young queens and males produced at the end of the life cycle in different colonies of first generation were mated in laboratory conditions. Mated queens were placed in a refrigerated incubator for their two months diapause period. After the diapause period, all queens were raised under the same conditions, and second generation colonies were reared. Some characters such as first egg-laying time, the timing of switch point, the timing of competition point, and total numbers of individuals produced in colonies of the first and second generation were determined. In these characteristics, the total numbers of workers and queens were found to be statistically significant between generations (p < 0.05). According to the findings of this study, some of the features such as first egglaying time, the timing of switch point, and the number of young queens produced may be unsatisfactory for mass production.

IRP30 promotes worker egg-laying in bumblebee, Bombus terrestris (Hymenoptera: Apidae).

Bumblebees are important pollinators that have evolved between solitary and advanced eusocial insects. Compared with advanced honeybees, workers of social bumblebee species are prone to laying eggs during the competition phase, which leads to the end of the colony. Therefore, worker reproductive behavior has become a popular research topic for exploring various biological phenomena. Here, we demonstrate a novel reproduction-related function of an immune response protein-encoding gene (Immune Responsive Protein 30, IRP30) in Bombus terrestris by employing RNA interference (RNAi) and a transgenic Drosophila melanogaster system. The results show that worker egg-laying was significantly affected by IRP30 expression levels (P<0.01). Compared with those in the dsGFP-treated groups, the first egg-laying time was delayed by 3.7 d and the egg number was decreased by 41% in the dsIRP30-treated group. In addition, the average size of the largest oocyte and the relative mRNA expression levels of Vg (vitellogenin) were significantly reduced in the dsIRP30-treated group (P<0.05). Cellular localization by immunofluorescence demonstrated that IRP30 has important functions in the germ cells of workers' ovarioles. Overexpression of IRP30 was confirmed to increase the reproductive capability of the transgenic D. melanogaster. In conclusion, IRP30 regulates worker egg-laying by affecting the expression of Vg, the size of the ovary and the formation of the oocyte. These findings provide essential information for understanding the mechanisms underlying worker reproductive regulation.

Maize hybrid and nutrient specific evaluation of the population dynamics and damage of the western corn rootworm (Diabrotica Virgifera Virgifera LeConte) in a long-term field experiment

AbstractAgricultural production is threatened by different invasive species, as their damage results in a serious loss of income. The aim of the research was the assessment of the swarming dynamics and damage of the western corn rootworm (WCR) adults and larvae. The experiment was carried out in monoculture fertilization long-term experiments and three maize hybrids compared for their reaction against WCR adult and larval damage under non-infested plots at different nitrogen levels. Differences among the hybrids have a lower effect on the damage of corn rootworm adults and larvae than the amount of applied nitrogen. The phosphorus-potassium are optimal levels, while nitrogen ranges from 0 to 300 kg and no nutrient supply took place in the control plots for 30 years. The number of adults located and feeding on the styles of the female flower recorded and the damage caused on the roots by larvae ranked on a modified Iowa scale. Nitrogen fertilization resulted in a change in the silking time. The lowest root damage observed in the case of the high nutrient treatment with an Iowa value of 3.18. The coincidence of the nourishment of adults and the egg-laying time with silking is a potential threat in terms of fertility. Based on the results, it found that the extent of root damage can be reduced through the optimal selection of the time and dose of nutrient supply, primarily that of nitrogen. In general, both larvae and adults can cause severe yield loss, but the method of control against them is different. The coincidence of the nourishment of adults and the egg-laying time with silking is a potential threat in terms of fertility.

Characterization of a Vitellogenin Receptor in the Bumblebee, Bombus lantschouensis (Hymenoptera, Apidae).

The vitellogenin receptor (VgR) belongs to the low-density lipoprotein receptor (LDLR) family, responsible for mediating the endocytosis of vitellogenin (Vg) into the ovaries to promote ovarian growth and oviposition. Here, we cloned and measured VgR gene expression characteristics in the bumblebee Bombus lantschouensis. RNA interference was used to validate VgR function. The results showed that the full length of the BLVgR cDNA was 5519 bp, which included a 5280 bp open reading frame encoding 1759 amino acids (AAs). Sequence alignment revealed that the protein contained 12 LDLa, 5 EGF, 2 EGF-CA and 10 LY domains. Phylogenetic analysis showed that BLVgR and the VgR of Bombus terrestris clustered together and the tree of bumblebees (Bombus) appeared as one clade next to honeybees (Apis). Transcript expression analysis showed that BLVgR was expressed in all tested tissues and showed the highest abundance in the ovaries. BLVgR expression was present in all developmental stages. However, the expression level in larvae was extremely low. In addition, the expression of BLVgR was significantly upregulated after egg laying in both workers and queens. In new emerging workers injected with 5 µg of VgR dsRNA, the expression level of BLVgR was 4-fold lower than that in the GFP dsRNA-injected group after 72 h. Furthermore, BLVgR silencing significantly reduced the number of eggs laid (3.67 ± 1.96 eggs) and delayed the first egg-laying time (16.31 ± 2.07 days) in worker microcolonies when compared to dsGFP (37.31 ± 4.09 eggs, 8.15 ± 0.22 days) and DEPC-treated water injected controls (16.42 ± 2.24 eggs, 10.00 ± 0.37 days). In conclusion, the BLVgR gene and its reproductive function were explored in the bumblebee B. lantschouensis. This gene plays an important role in egg laying time and egg number.

Influence of nest-floor slope on the nest choice of laying hens

Group nests in alternative housing systems for laying hens primarily fulfil the hen's needs for seclusion and protection. Commercial nests used in Switzerland are built according to the provisions of the Swiss Animal Welfare Legislation. However, nest types can differ in aspects, such as floor slope, that could have an impact on egg-laying behaviour. Floor slope has to be designed so that eggs roll away without breaking and so that hens feel comfortable laying their eggs. In commercial nests, the slope is usually between 12% and 18%. The aim of this study was to investigate the effect of floor slope on the hen's nest preference and laying behaviour. We predicted that hens would prefer nests with a lower sloped floor for evolutionary reasons and for reasons related to comfort. Eight pens, each with 17–18 white laying hens (LSL), were equipped with two roll-away nests (0.54 m 2) having different floor slopes (12% and 18%). Eggs were collected each day (from approximately 20 weeks of age until 28 weeks of age); the number of eggs in each nest and on the floor of the pens was recorded. Behaviour inside the nest was filmed for two consecutive days during the main egg-laying time from the second hour to the fifth hour (4 h) after lights came on in week 27/28. The following data were recorded: number of hens in each nest, the nest visits/egg number ratio, the number of sitting events, the body alignment of hens sitting in the nest and the number and duration of nest visits. Data were analysed with a repeated-measures ANOVA. There was no difference between the numbers of eggs in the two nests, but more hens were counted in nests with a 12% slope ( p = 0.027). The ratio between the number of nest visits and number of eggs did not differ significantly between the nests. However, we counted more sitting events in the nest with 12% slope ( p = 0.007). The percentage of body alignment towards the back ( p = 0.044) and towards the front ( p = 0.028) of the nest differed between the nests. Furthermore, for nest visits lasting between 10 and 90 min, we found significant differences in the total number of nest visits ( p = 0.039). For visits in this range of duration, we also found significant differences for nest visits with sitting ( p = 0.025) and for the number of nest visits with egg laying ( p = 0.049). All of these differences favoured the 12% nest. Both nests were generally accepted by the hens. However, because of the higher number of hens counted in the 12% nest and the higher amounts of nest visits and sitting events found in these nests, we recommend to use nests with a floor slope of 12% rather than 18%.

Egg laying and egg laying behavior of Red Palm Weevil, Rhynchophorus ferrugineus (Olivier) 1790 (Coleoptera: Curculionidae)

Red Palm Weevil is a key pest of palm trees worldwide. Various studies have been conducted on life history and behavior of RPW, however some key points in egg laying period is still missing. The purpose of this study was to investigate the egg-laying timing as a number of egg /day /female, time interval between egg laying event and the female bio-etiological needs while ovipositing. The study was carried out through recording the behavior of adults with PC-driven video cameras equipped with natural bright and artificial IR light source. RPW was collected and allowed to lay eggs on Phoenix canariensis petiole. The number of eggs per day is variable according to time and female age; the average number of eggs per event is 4.13. Moreover egg laying timing and the time of deposition are quite variable while eggs can be laid anytime during the day and night. The average egg-laying time was 54.52 sec. The observations showed that the females need to fly, feed and mate before egg laying process.

Interannual variations of reproductive parameters in a booted eagle (Hieraaetus pennatus) population: the influence of density and laying date

A population of booted eagles (Hieraaetus pennatus) consisting of 21–29 pairs was studied for 7 years (1998–2004) in a forested mountainous region of southeastern Spain. The average egg-laying time was 25 April (earliest 31 March, latest 26 May). Sixty-eight percent of territorial pairs produced eggs, and 81% of reproductive pairs successfully raised at least one offspring. Mean clutch size was 1.91 eggs, and 84% hatched. The survival rate of chicks was high, with only 17% dying. The major known cause of nestling mortality was predation, mainly by the Eurasian eagle owl (Bubo bubo). The mean number of flying offspring was 0.91 per territorial pair, 1.29 per reproductive pair and 1.65 per successful pair. All population breeding parameters analysed were density independent, but most showed a significantly negative relationship with mean laying date.

Oviposition Behavior of &lt;I&gt;Stenoma catenifer&lt;/I&gt; (Lepidoptera: Elachistidae): Chemical and Physical Stimuli and Diel Pattern of Egg Laying

The influence of chemical and physical stimuli on the diel patterns of oviposition behavior of the borer Stenoma catenifer Walsingham (Lepidoptera: Elachistidae) were investigated. All experiments were conducted in the laboratory (25 ± 2°C, 60 ± 20% RH, photoperiod of 14:10 [L:D] h) by using five pairs per cage (n = 5). To evaluate response to chemical stimulation, the cages were lined internally with a paper towel containing different treatments: 1 and 2) avocado fruit of ‘Margarida’ and ‘Breda’, 3) artificial fruit, and 4) no fruit (natural or artificial). Quilted paper towel, nonquilted paper towel, and a smooth sheet of paper were used to evaluate response to the substrate. The numbers of eggs in all treatments that included avocado fruit were statistically higher than the others. Likewise, the numbers of eggs on quilted paper towel were statistically higher than on nonquilted paper towel or on smooth paper. The peak egg-laying time in the laboratory occurred from 2000 to 2400 hours.

The Effects of an “El Niño” Southern Oscillation Event on Reproduction in Male and Female Blue-Footed Boobies,Sula nebouxii

This study attempted to determine endocrine correlates of reproductive success in relation to major deleterious environmental conditions. In 1992, an El Niño southern oscillation event resulted in complete reproductive failure in a colony of blue-footed boobies,Sula nebouxi,on Isla Isabel in the Pacific Ocean off San Blas, Nayarit, Mexico (21.5°N, 105.5°W). In 1993, the El Niño event had waned and reproductive success was high. The mean sea surface temperature in 1992 was 26.69°, the warmest year for 11 years of data (mean, 25.63°). In 1993, mean sea surface temperature was 25.75°. Plasma levels of testosterone were highest during the egg-laying period in 1993 and declined markedly during incubation. There were no differences between males and females. Comparisons of testosterone levels between 1992 and 1993 (egg-laying time point removed for 1993) showed no significant differences. Thus reproductive failure during an El Niño year was not related to testosterone levels. Baseline plasma levels of corticosterone did not change over the nesting cycle in either sex. There was a trend for plasma levels of corticosterone to be higher in males and females during the earlier stages of breeding in 1992 compared with 1993, and if all levels were combined within years then females showed significantly higher plasma levels of corticosterone in the El Niño year. Plasma levels of corticosterone showed marked increases following capture and handling in both sexes and at every stage of the breeding cycle in each year. There was no variation in the adrenocortical responses to stress with year or stage of nesting in males. However, in females, maximum corticosterone levels were greatest during the parental phase of 1992, the El Niño year, when all nests ultimately failed. Comparisons of the dynamics of corticosterone changes during the capture stress protocol revealed no correlations with body mass in 1992 or 1993. These data suggest that although massive reproductive failure in the El Niño year was not related to testosterone levels, baseline circulating concentrations of corticosterone may have a role in inhibiting onset of breeding. In contrast, after the nesting cycle has been initiated, increased adrenocortical sensitivity to acute stress may be involved in nest abandonment.

Time of Day of Ovulation by Three Duck Species in Subarctic Alaska

I examined variation in ovulation times of Northern Pintails (Anas acuta), American Wigeon (A. americana), and Lesser Scaup (Aythya affinis) breeding in subarctic Alaskan wetlands. Ovulation times and, by extension, egg-laying times were highly variable in all three species, with ovulations occurring during all hours of the day. Only Lesser Scaup demonstrated a morning peak in ovulations, within a broad range of ovulation times. Lack of a distinct time of day of ovulation suggests that fitness is not related to egg-laying time for these species, particularly at subarctic latitudes with nearly perpetual daylight. Egg-laying interval may have more adaptive significance than egg-laying time for these species. Ovulation intervals were estimated to be approximately 24 hr, which is short relative to the range of intervals documented in birds, despite high energetic and nutritional costs of egg formation in these species. Evidence of approximately 24-hr ovulation intervals, particularly in the absence of a distinct time of day for egg laying, supports hypotheses that a shortened period of egg production in waterfowl may have selective advantage due to reduction in the period of nest exposure to predation, earlier hatch dates, reduced hatch asynchrony, or improved viability of early-laid eggs.

Egg-Laying Time and Laying Interval in the Common Eider

We determined the time of day at which eggs were laid and the laying interval (time between laying of successive ggs in a clutch) in the Hudson Bay race of the Common Eider (Somateria mollissima sedentaria), at La P6rouse Bay, Churchill, Manitoba (58?24'N, 94?24'W). Nests were found at the one-egg stage and were subsequently visited three times daily. Analysis of the nest contents at each visit allowed us to estimate mean egg-laying times as well as the mean time at which eggs were lost to predators. The estimated mean egg-laying hour was 13:49 (CST, 95% CL 12:30-15:06). We detected no selective advantage to laying at this time based on the timing of egg predation. The average gg-laying interval was 27.7 + 3.4 hr. Laying intervals decreased with increasing clutch sizes. For clutches of four and five eggs, the estimated interval between the last two eggs was significantly onger than that for intervals between all other eggs, all other comparisons between intervals were not significantly different. If last-laid eggs were excluded the mean laying interval for all eggs was 26.1 + 4.3 hr, confirming that the last egg in a clutch takes longer to produce. We suggest hat longer laying intervals of last-laid eggs may be related to hormonal changes associated with the onset of incubation.

Life History Variation in a Population of the Australian Frog Ranidella signifera: Time of Egg Laying

The seasonal timing of reproductive events is considered an important aspect of the life history of animals (Harris, 1980; Alford and Wilbur, 1985; Weis and Abrahamson, 1985; Wilbur and Alford, 1985; Alford, 1989a, b, c; Dangerfield and Telford, 1990) and plants (Rathcke and Lacey, 1985; Miller, 1987). Timing may be under strong selective pressure because an individual's entire reproductive output for a season may be lost or significantly reduced if produced at the wrong time (Harris, 1980; Weis and Abrahamson, 1985). When optimal conditions for offspring growth and survival occur at a particular time, selection should favor individuals whose production of offspring coincides with those conditions. Conversely, longer breeding periods may result if offspring success either does not vary with time or is unpredictable. Among anuran amphibians there is interspecific variation in the length of the breeding season ranging from a few days to many months (Wells, 1977). Egg and larval survival may influence the period over which adults breed. Three factors can vary with time of egg laying to influence success of eggs and larvae. First, temperature and duration of water bodies containing larvae may change with season (Harris, 1980). Second, the community of predators, competitors and food resources coexisting with the tadpoles may also change during a season (Wilbur and Alford, 1985; Alford, 1989a, b; Morin et al., 1990). Third, the quality of eggs laid by females may vary over a season because females breeding at different times differ either in age or in the environmental conditions they experienced during vitellogenesis (Kaplan, 1987), or because evolutionary pressures may have led to females producing eggs of different quality at different times in response to predictable variations in the environment experienced by the tadpoles (Smith and Fretwell, 1974; Wilbur, 1977a; Crump, 1984). Ranidella signifera is an Australian frog which has a prolonged breeding season (Humphries, 1979; MacNally, 1979). It breeds in a range of winter-filled temporary water bodies over its distribution in southeast Australia. In a population near Bridgewater in the Adelaide Hills, South Australia, breeding extends from March to November, and peaks from mid-winter

The effects of temperature on development of the large narcissus fly (Merodon equestris)

Eggs, larvae, pupae and adults of the large narcissus fly (Merodon equestris) were reared at a series of constant temperatures between 9–24°C. Egg development required from 37 days at 9°C to 7 days at 21.5°C. The low-temperature threshold for development was 6.7°C. Larvae reared at 1424°C were fully-grown after 18 weeks, but it took much longer for such insects to pupate, and adult flies emerged only after about 45 weeks of development. Large narcissus flies enter diapause during the larval stage and overwinter as fully-fed larvae, forming pupae in the following spring. Post-winter pupation and pupal development took from 169 days at 10°C to 36 days at 21.5°C. Of this, pupal development required from 91 days at 10°C to 19 days at 21.5°C. The low-temperature threshold for post-winter pupation and pupal development was 7.1°C, and for pupal development alone, 7.2°C. Females maintained at or below 19°C laid few eggs, whereas some females kept at or above 21.5°C laid more than 100 eggs (mean 69 ± 36). Approximately 50% of females maintained at or above 21.5°C laid less than 10 eggs during their lifetime. The mean egg-laying time was 6 to 9 days. Although temperatures at or below 19°C inhibited mating, once a female had mated, such temperatures did not prevent oviposition.