Reproductive Response of Aphelinus perpallidus (Hymenoptera: Aphelinidae) to Age of Its Parent and Density of Its Host, Monellia caryella (Homoptera: Aphidae)

1987 ◽  
Vol 16 (4) ◽  
pp. 877-880 ◽  
Author(s):  
R. Bueno ◽  
J. D. Stone
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Ruby E. Harrison ◽  
Mark R. Brown ◽  
Michael R. Strand

Abstract Background Most female mosquitoes are anautogenous and must blood feed on a vertebrate host to produce eggs. Prior studies show that the number of eggs females lay per clutch correlates with the volume of blood ingested and that protein is the most important macronutrient for egg formation. In contrast, how whole blood, blood fractions and specific blood proteins from different vertebrates affect egg formation is less clear. Since egg formation is best understood in Aedes aegypti, we examined how blood and blood components from different vertebrates affect this species and two others: the malaria vector Anopheles gambiae and arbovirus vector Culex quinquefasciatus. Methods Adult female mosquitoes were fed blood, blood fractions and purified major blood proteins from different vertebrate hosts. Markers of reproductive response including ovary ecdysteroidogenesis, yolk deposition into oocytes and number of mature eggs produced were measured. Results Ae. aegypti, An. gambiae and C. quinquefasciatus responded differently to meals of whole blood, plasma or blood cells from human, rat, chicken and turkey hosts. We observed more similarities between the anthropophiles Ae. aegypti and An. gambiae than the ornithophile C. quinquefasciatus. Focusing on Ae. aegypti, the major plasma-derived proteins (serum albumin, fibrinogen and globulins) differentially stimulated egg formation as a function of vertebrate host source. The major blood cell protein, hemoglobin, stimulated yolk deposition when from pigs but not humans, cows or sheep. Serum albumins from different vertebrates also variably affected egg formation. Bovine serum albumin (BSA) stimulated ovary ecdysteroidogenesis, but more weakly induced digestive enzyme activities than whole blood. In contrast, BSA-derived peptides and free amino acids had no stimulatory effects on ecdysteroidogenesis or yolk deposition into oocytes. Conclusions Whole blood, blood fractions and specific blood proteins supported egg formation in three species of anautogenous mosquitoes but specific responses varied with the vertebrate source of the blood components tested.


Birds ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 114-126
Author(s):  
Marek Panek

Predators can modify their diet and demography in response to changes in food availability and habitat quality. I tested the prediction that some species can change their predation pattern, between specialist type and generalist type, depending on the complexity of habitat structure. It was hypothesized that their dietary response is stronger in diversified habitats than in simplified ones, but the opposite tendency occurs in the case of reproductive response. The nestling diet and breeding success of the Eurasian Buzzard Buteo buteo, the abundance of its main prey (the common vole Microtus arvalis), and that of the most important alternative prey group (passerines) were estimated over ten years in two types of agricultural habitat in western Poland, i.e., in the diversified habitat of small fields and the simplified habitat of large fields. The vole abundance was higher in large fields, but the abundance of passerines was greater in small fields. The frequency of voles in the Eurasian Buzzard nestling diet was higher in large fields than in small fields and increased with the abundance of this prey in crop fields. However, no difference in the relationship between the vole frequency in the diet of Eurasian Buzzards and the abundance of voles was found between the two habitat types. The breeding success of Eurasian Buzzards was dependent on the vole abundance, but this relationship did not differ between the two field types. It seems that the pattern of dietary and reproductive response of Eurasian Buzzards depends on the actual availability of individual prey species, which can be modified by habitat quality, rather than on relative prey abundance.


BioControl ◽  
2014 ◽  
Vol 59 (6) ◽  
pp. 697-705 ◽  
Author(s):  
Daiane Celestino ◽  
Guilherme I. Braoios ◽  
Rodrigo S. Ramos ◽  
Lessando M. Gontijo ◽  
Raul Narciso C. Guedes

2014 ◽  
Vol 62 (5) ◽  
pp. 369 ◽  
Author(s):  
Annette M. Muir ◽  
Peter A. Vesk ◽  
Graham Hepworth

Intervals between fires are critical for the persistence of obligate-seeding shrubs, and are often used in planning fires for fuel reduction and biodiversity conservation in fire-prone ecosystems worldwide. Yet information about the trajectories of reproductive performance for such species is limited and information is often qualitative. To test existing assumptions about reproductive maturity periods for eight obligate-seeding shrubs (with both canopy and soil seedbanks) in foothill forests of south-eastern Australia, we used a chronosequence approach, with sites from 2 years to >40 years post-fire. Quantitative measurements of flowering and fruiting were used to fit models of reproductive response in relation to time-since-fire for each species. Inferred reproductive maturity for each species, based on modelled times to reach 80% of maximum flower production, varied from 5 to 18 years post-fire. For a subset of three species, models predicted 80% maximum seed production occurring 1–7 years later than flowering. Our results confirmed or extended assumptions about post-fire reproductive maturity for these species, and provided a basis for improved incorporation of plant life-history in ecological fire planning. We infer that increased fire frequency makes one of our study taxa, Banksia spinulosa var. cunninghamii (Sieber ex Rchb.) A.S.George, vulnerable to decline because of its long reproductive maturity period and serotinous seed storage.


1995 ◽  
Vol 1995 ◽  
pp. 95-95
Author(s):  
Linda M Mitchell ◽  
Margaret E King ◽  
R.P. Aitken ◽  
Jacqueline M Wallace

There is increasing interest in the development of later lambing systems for crossbred ewes which more closely match ewe nutritional requirements with herbage growth (Stone, 1988; Mitchell, 1990). It has long been recognised however that at extremes of the natural breeding season fecundity is reduced, a possible consequence of seasonal variations in ovulation rate, fertilisation and/or embryo survival (Hammond, 1944). Daylength is the factor which entrains the endogenous rhythm of reproduction in sheep (Donovan, O’Callaghan, Karsh, Boland and Roche, 1992) and daylength changes per se may be responsible for variations in reproductive response throughout the breeding season. Associated environmental and management factors may also be of importance. The objective of the present study was to determine the effect of management history and month of mating on ovulation and lambing rates in Mule ewes.


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