Influence of intraspecific larval competition and mating on the longevity and reproductive performance of females of the leaf miner Agromyza frontella (Rondani) (Diptera: Agromyzidae)

1984 ◽  
Vol 62 (11) ◽  
pp. 2197-2200 ◽  
Author(s):  
Daniel T. Quiring ◽  
Jeremy N. McNeil

Longevity and fecundity of mated and unmated Agromyza frontella females were positively related to pupal weight which was determined by the degree of intraspecific larval competition to which individuals had been subjected. The incidence of egg eclosion for mated females was also positively correlated to pupal weight. Unmated females lived longer, started ovipositing later following emergence, and had a lower mean daily and total fecundity than mated females, which supports the hypothesis of a trade-off between reproductive output and longevity. However, a positive relationship existed between fecundity and longevity for both mated and unmated females, as well as between high early egg production and longevity for mated females.

2018 ◽  
Author(s):  
Gregory M. Kohn

ABSTRACTPair bonds are often maintained through the reciprocal and coordinated exchange of communicative signals. The ability to recognize and appropriately respond to a partner’s signals will define a pair’s ability to reproduce. Individual variation in responsiveness, by shaping the formation and maintenance of strong pair bonds, will ultimately influence an individual’s reproductive output. Throughout the breeding period, female cowbirds (Molothrus ater) respond to male song displays using a vocalization known as the chatter. In this study, we investigated whether variation in chatters remained repeatable across years and predicted reproductive performance. A flock of cowbirds housed in a large aviary complex was observed during the spring of 2011 to 2012. We recorded courtship interactions, including singing behavior for males, and chatters and eggs laid by females. The rate with which females responded to song using chatters remained consistent across years, with some females predictably responding to more songs using chatters than others. During 2012, chattering predicted the number of eggs females laid and her paired status. Paired females were more likely to respond to songs with chatters, and there was a strong positive relationship between the number of eggs laid and the proportion of songs she responded to using chatters. Overall, these findings suggest that individual variation in female vocal responsiveness is an important contributing factor to cowbird reproductive success.


1984 ◽  
Vol 62 (3) ◽  
pp. 421-427 ◽  
Author(s):  
Daniel T. Quiring ◽  
Jeremy N. McNeil

The effect of competition among similarly aged larvae of the alfalfa blotch leaf miner, Agromyza frontella (Rondani), was investigated in laboratory studies over a range of larval densities (1–10 larvae per leaflet) commonly found on alfalfa in Quebec. In these studies A. frontella larvae were found to be resource limited when developing in small leaflets and (or) with other larvae. Larval mortality owing to interference (cannibalism) during the first two larval instars, and exploitation (starvation) competition during the third and final instar, increased in a density-dependent manner. Prepupal and pupal mortality increased and pupal weight decreased as larval density increased. However, pupal developmental rates and adult sex ratios of survivors were not significantly affected by larval density. Interference competition during the first two larval instars reduced larval density and thus diminished the probability that third-instar larvae would be subjected to exploitation competition. These findings were confirmed under field conditions.


Intermittent Lighting Improves the Efficiency of Artificial Insemination in Cage Housed Laying Hens Kavtarashvili A.Sh., Kolokolnikova T.N. Federal Scientific Center “All-Russian Research and Technological Poultry Institute” of Russian Academy of Sciences Omsk Agrarian Scientific Center Summary: The effects of different lighting regimes on the oviposition schedule, productive performance, and reproductive efficiency in cage housed laying hens of layer parental flock (Hisex White-R) were studied; the reasonable regime of artificial insemination (AI) under intermittent lighting is proposed. It was found that intermittent lighting regime 1L:4D:4L:1D:4L:10D compared to the constant lighting significantly alters oviposition schedule: under this regime 82.3% of all daily eggs were laid until 9 am (vs. 66.6% in control). This regime and AI at 10 am improved the productive and reproductive performance compared to control (constant lighting 16L:8D and AI at 12 am): mortality by 1.9%, egg production per initial hen by 3.8%, egg weight by 1.1%, percentage of eggs suitable for incubation by 1.9%, egg fertility by 0.9%, hatchability by 2.3%, hatch of chicks by 2.9%, feed conversion ratio (kg of feed per 10 eggs) by 5.3%, the expenses of electric energy for lighting (per 1000 eggs suitable for incubation) by 54.5%. Key words: INTERMITTENT LIGHTING, CAGE HOUSED LAYERS, ARTIFICIAL INSEMINATION (AI), OVIPOSITION SCHEDULE, AI TIMING, PRODUCTIVE PERFORMANCE, REPRODUCTIVE PERFORMANCE


1989 ◽  
Vol 67 (6) ◽  
pp. 1599-1602 ◽  
Author(s):  
Vital Boulé ◽  
Gerard J. Fitzgerald

Female threespine sticklebacks (Gasterosteus aculeatus) spend only 9–15 days on the spawning grounds, an intertidal salt marsh at Isle Verte, Quebec, during a 2-month breeding season. Individuals average only one spawning. However, in the laboratory they lay clutches of several hundred eggs every 3–5 days for several months. We designed laboratory experiments to determine (i) whether daily temperature fluctuations similar to those encountered in the marsh affect reproduction (number of clutches, number of eggs per clutch, and size of eggs) and (ii) whether the amplitude of the fluctuations encountered by the fish affects reproduction. We compared the reproduction of females held in fluctuating temperatures with that of females kept at 20 °C. Fish kept under fluctuating conditions produced more eggs per clutch but had longer interspawning intervals than those at 20 °C. Total seasonal egg production and egg size did not differ between the two groups. Fish in fluctuating temperatures survived longer and were in better condition than those at 20 °C. We conclude that the amplitude of the fluctuations is less important than mean temperature in determining reproductive performance. Fluctuating temperatures on the spawning grounds are not responsible for the short residency there.


Author(s):  
S.-H. Kim ◽  
H. Park ◽  
W. Kim ◽  
J.-H. Song ◽  
S.J. Roh ◽  
...  

The establishment of efficient and sustainable production of industrially important insects necessitates the detailed knowledge of the optimal mixture of macronutrients required for maximising their performance and fitness. The white spotted flower chafer, Protaetia brevitarsis (Coleoptera: Scarabaeidae: Cetoniinae), is one of the most important edible insects in East Asia with high nutritional and medicinal value. Here, we report how the ratio of protein to digestible carbohydrate (P:C) in the diet influenced lifespan and reproductive performance in the adults of P. brevitarsis. Throughout their lifespan, beetles were fed ad libitum one of five diets with differing P:C ratio (0:1, 3:7, 1:1, 7:3, 1:0). Both lifespan and the number of eggs produced over the lifetime were maximised at the P:C ratio of 3:7 and declined as the ratio deviated away from this optimal P:C composition. Beetles fed a diet containing only protein (P:C 1:0) not only had the shortest lifespan but also exhibited substantially reduced lifetime egg production compared to those fed the other diets. However, the effects of dietary P:C ratio on daily egg production rate and egg hatchability were marginal. The number of eggs produced at each age stage peaked at the age of week 2 and then gradually declined with increasing age, showing the sign of reproductive senescence. Age-specific egg production was higher in beetles confined to three intermediate P:C ratios (3:7, 1:1, 7:3) than those confined to two extreme P:C ratios (0:1, 1:0) throughout their lifespan. The speed of age-related decrease in reproductive performance was the slowest at P:C 3:7. Our data have implications for optimising the production of this edible insect with emerging economic importance.


2016 ◽  
Vol 74 (3) ◽  
pp. 103-109 ◽  
Author(s):  
Ouratul Edritanti ◽  
Achmad Farajallah ◽  
Yusli Wardiatno

Abstract Emerita emeritus is an abundant species in Bengkulu coastal waters, but the knowledge of its reproductive biology is poor. The present study was conducted to elucidate the reproductive aspects of ovigerous female E. emeritus, including fecundity, egg volume and reproductive output. This study was conducted between January 2015 and January 2016 in Bengkulu coastal waters, Indonesia. Samples were collected manually using shovels and hands. The results showed that ovigerous females occurred every month. Fecundity increased significantly in ovigerous females proportional to the size. No correlation was shown between sea surface temperature and egg production. Fecundity and reproductive output decreased throughout the embryonic development.


2021 ◽  
Author(s):  
Tom Sarraude ◽  
Bin-Yan Hsu ◽  
Suvi Ruuskanen ◽  
Ton Groothuis

Maternal hormones constitute a key signalling pathway for mothers to shape offspring phenotype and fitness. Thyroid hormones (THs; triiodothyronine, T3 and thyroxine, T4) are metabolic hormones known to play crucial roles in embryonic development and survival in all vertebrates. During early developmental stages, embryos exclusively rely on the exposure to maternal THs, and maternal hypothyroidism can cause severe embryonic maldevelopment. The TH molecule includes iodine, an element that cannot be synthesised by the organism. Therefore, TH production may become costly when environmental iodine availability is low. This may yield a trade-off for breeding females between allocating the hormones to self or to their eggs, potentially to the extent that it even influences the number of laid eggs. In this study, we investigated whether low dietary iodine may limit TH production and transfer to the eggs in a captive population of Rock pigeons (Columba livia). We provided breeding females with an iodine-restricted (I- diet) or iodine-supplemented diet (I+ diet) and measured the resulting circulating and yolk iodine and TH concentrations and the number of eggs laid. Our iodine-restricted diet successfully decreased both circulating and yolk iodine concentrations compared to the supplemented diet, but not circulating or yolk THs. This indicates that mothers may not be able to independently regulate hormone exposure for self and their embryos. However, egg production was clearly reduced in the I- group, with fewer females laying eggs. This result shows that restricted availability of iodine does induce a cost in terms of egg production. Whether females reduced egg production to preserve THs for themselves or to prevent embryos from exposure to low iodine and/or THs is as yet unclear.


2012 ◽  
Vol 279 (1749) ◽  
pp. 4893-4900 ◽  
Author(s):  
Benjamin G. Fanson ◽  
Kerry V. Fanson ◽  
Phillip W. Taylor

The trade-off between lifespan and reproduction is commonly explained by differential allocation of limited resources. Recent research has shown that the ratio of protein to carbohydrate (P : C) of a fly's diet mediates the lifespan–reproduction trade-off, with higher P : C diets increasing egg production but decreasing lifespan. To test whether this P : C effect is because of changing allocation strategies (Y-model hypothesis) or detrimental effects of protein ingestion on lifespan (lethal protein hypothesis), we measured lifespan and egg production in Queensland fruit flies varying in reproductive status (mated, virgin and sterilized females, virgin males) that were fed one of 18 diets varying in protein and carbohydrate amounts. The Y-model predicts that for sterilized females and for males, which require little protein for reproduction, there will be no effect of P : C ratio on lifespan; the lethal protein hypothesis predicts that the effect of P : C ratio should be similar in all groups. In support of the lethal protein hypothesis, and counter to the Y-model, the P : C ratio of the ingested diets had similar effects for all groups. We conclude that the trade-off between lifespan and reproduction is mediated by the detrimental side-effects of protein ingestion on lifespan.


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