Latitudinal variation in the sociality of allodapine bees (Hymenoptera: Apidae): sex ratios, relatedness and reproductive differentiation

2001 ◽  
Vol 49 (1) ◽  
pp. 1 ◽  
Author(s):  
Adam L. Cronin ◽  
Michael P. Schwarz
Keyword(s):  
Sex Allocation ◽  
Sympatric Species ◽  
Egg Laying ◽  
Reproductive Skew ◽  
Brood Development ◽  
Eastern Australia ◽  
Reproductive Differentiation ◽  
Allocation Patterns ◽  
One Year ◽  
Latitudinal Range

Variation in sociality of two Australian allodapine bees was investigated over a latitudinal range of 10˚, spanning subtropical to cool temperate forests in eastern Australia. Exoneura robusta is univoltine and singly brooded in southern populations but is able to produce two broods per season in northern populations, leading to opportunities for sib rearing by older brood members. In contrast, sympatric colonies of E. angophorae show no such variation with latitude, and all populations exhibit some colonies where opportunities for sib rearing arise. Patterns of ovarian differentiation, relatedness and sex allocation were examined over a one-year period for these two sympatric species in four populations. Within each species, the timing of ovarian development and the degree of reproductive skew were similar at all sites, but the onset of egg-laying and brood development was earlier in E. angophorae than in E. robusta. Relatedness and sex allocation patterns in northern populations of these species were not markedly different from southern populations. Selection for female-biased sex allocation and high reproductive skew in Exoneura probably stems from strong benefits from cooperative nesting, and our results suggest that opportunities for sib rearing (and eusociality) in these species may depend on latitudinally mediated brood development rates, and are unrelated to levels of sex bias and relatedness.

Breeding biology of the Critically Endangered Tahiti MonarchPomarea nigra, a bird with a low productivity

2017 ◽  
Vol 28 (4) ◽  
pp. 606-619 ◽  
Author(s):  
CAROLINE BLANVILLAIN ◽  
THOMAS GHESTEMME ◽  
TEHANI WITHERS ◽  
MARK O’BRIEN
Keyword(s):  
Reproductive Success ◽  
French Polynesia ◽  
Egg Laying ◽  
Breeding Biology ◽  
Critically Endangered ◽  
Tropical Island ◽  
Island Endemics ◽  
Nest Activity ◽  
Considerable Length ◽  
One Year

SummaryWe studied the breeding biology of Tahiti MonarchPomarea nigra, a ‘Critically Endangered’ forest bird endemic to Tahiti (French Polynesia). Nest activity was monitored from 1998 to 2002, and again from 2008 to 2015. During these 12 years, only 2–13 breeding pairs per year produced hatchlings. Egg-laying occurred all year, but usually increased between August and January, peaking around November. Of the 200 nests monitored, 33 (16%) were abandoned shortly after construction, 71 had an egg laid immediately after the nest were completed (34 %) and 96 nests (46 %) had a pre-incubation phase of 18.9 ± 1.9 days (3–62 days;n= 47 nests), during which the birds visited the nest on an irregular basis. Half (49 of 96) of these nests were abandoned before an egg was laid, with incubation subsequently commencing at the remaining nests (n= 47). Although both sexes incubated for an average of 13.6 ± 0.3 days (range 13–15), the female usually spent more time incubating than the male. Only one young per nest was ever observed. The average nestling phase was 15.5 ± 0.7 days (range 13 to 20 days). Parents continue to feed the young after fledging for 74 ± 4.7 days (range 42–174). As with many tropical island endemics, the Tahiti Monarch has low reproductive productivity as indicated by the fact that: 1) only 56% of pairs attempt to lay an egg in any one year, 2) most pairs attempt only one brood per year and 3) the considerable length of the nesting and fledging phases. Because of its low productivity, maximising the reproductive success of the Tahiti Monarch is essential to secure its recovery.

Multi-Year Seasonal Sex-Allocation Patterns in Red-winged Blackbirds (Agelaius phoeniceus)

The Auk ◽  
2009 ◽  
Vol 126 (1) ◽  
pp. 181-185 ◽  
Author(s):  
Patrick J. Weatherhead
Keyword(s):  
Sex Allocation ◽  
Agelaius Phoeniceus ◽  
Allocation Patterns

scholarly journals A contribution to the study of biology of Curculio elephas Gyll. (Coleoptera, Curculionidae)

2011 ◽  
pp. 19-28
Author(s):  
Milan Drekic ◽  
Ljubodrag Mihajlovic
Keyword(s):  
Life Cycle ◽  
Larval Stage ◽  
Seed Orchard ◽  
Egg Laying ◽  
Pedunculate Oak ◽  
Minor Part ◽  
One Year ◽  
Entomological Laboratory ◽  
A Minor ◽  
Curculio Elephas

One of the insects that feeds on pedunculate oak acorns and reduces its seed yield is Curculio elephas Gyll. The study of Curculio elephas Gyll is necessary because of the severe damages caused by this insect and also owing to its insufficiently investigated biology. The research was conducted in the common oak seed orchard at Banov Brod, forest estate ?Sremska Mitrovica?, and in the entomological laboratory. The adults emerge from the soil chambers from mid July till the beginning of September. The presence of adults, as determined by crown fogging, ranged from the end of July till the beginning of September with the highest number in mid August. After emerging from the soil, females are already fertile with the developed eggs in the ovaries. They start egg laying after 1 to 8 days and they lay from one to seven eggs per day. Egg laying period lasts from 7 to 20 days. Fertility of C. elephas females ranges from 5 to 40 eggs, while their fecundity ranges from 19 to 45 eggs. At the end of the larval stage, larvae bore into the soil and stay there from one to three years. The species hibernates only in the larval stage. C. elephas has a one-year life cycle, while a minor part of the population has a two or three-year life cycle.

Reproductive biology of two sympatric colubrid snakes, Chironius flavolineatus and Chironius quadricarinatus, from the Brazilian Cerrado domain

2010 ◽  
Vol 31 (4) ◽  
pp. 463-473 ◽  
Author(s):  
Roberta Richard Pinto ◽  
Otavio Augusto Vuolo Marques ◽  
Ronaldo Fernandes
Keyword(s):  
Reproductive Biology ◽  
Sexual Maturity ◽  
Egg Production ◽  
Sympatric Species ◽  
Egg Laying ◽  
Reproductive Pattern ◽  
Brazilian Cerrado ◽  
Wet Season ◽  
Reproductive Cycles ◽  
First Time

AbstractThe reproductive biology of Chironius flavolineatus and C. quadricarinatus from the Brazilian Cerrado domain is described, including sexual maturity, female fecundity, and reproductive cycles of males and females. Egg-laying is recorded here for the first time for C. quadricarinatus. Males of both species attain sexual maturity with a smaller snout-vent length than females. Females of C. flavolineatus have an extended reproductive cycle with egg production during the wet season, whereas males exhibit year-round sperm production. Chironius quadricarinatus has continuous reproductive cycles in both sexes. Differences in reproductive pattern between these two sympatric species are probably related to phylogenetic constraints on intrageneric lineages of Chironius.

Social Behaviour in an Australian Allodapine Bee Exoneura (Brevineura) xanthoclypeata (Hymenoptera : Apidae)

1997 ◽  
Vol 45 (4) ◽  
pp. 385 ◽  
Author(s):  
Simon M. Tierney ◽  
Michael P. Schwarz ◽  
M. Adams
Keyword(s):  
Social Behaviour ◽  
Social Evolution ◽  
Extended Period ◽  
Sensu Stricto ◽  
Extensive Study ◽  
Egg Laying ◽  
Brood Production ◽  
Brood Rearing ◽  
Reproductive Differentiation ◽  
Two Factors

The allodapine bees are well suited for comparative studies of social evolution because of the wide variation in social behaviour within and between genera. There are three main clades in the endemic Australian genus Exoneura. Two groups (Exoneura sensu stricto and Exoneurella) have received extensive study. In this paper we provide the first detailed study of social behaviour in the third group, Brevineura, based on a heathland population of Exoneura (B.) xanthoclypeata Rayment. This species has two seasonal pulses of egg-laying and brood rearing occurs throughout most of the year, including winter. This extended period of egg-laying and brood development differs from the two other Australian Exoneura subgenera and provides extensive opportunities for eusocial-like sib-rearing. Dissection data indicate that reproductive differentiation among adult nestmates is well developed and dependent on body size, with smaller females being mostly or entirely non-reproductive. Per capita brood production is dramatically higher in multi-female nests than in single-female nests and relatedness between adult nestmates is moderately high (r ≈ 0·5). These two factors suggest that local fitness enhancement may be occurring and our limited sex allocation data suggest female-biased ratios. Because of the opportunities for sib-rearing in this species, local fitness enhancement has the potential to lower selective thresholds for eusociality.

scholarly journals Sex Allocation Patterns across Cooperatively Breeding Birds Do Not Support Predictions of the Repayment Hypothesis

2017 ◽  
Vol 190 (4) ◽  
pp. 547-556 ◽  
Author(s):  
Nyil Khwaja ◽  
Ben J. Hatchwell ◽  
Robert P. Freckleton ◽  
Jonathan P. Green
Keyword(s):  
Sex Allocation ◽  
Breeding Birds ◽  
Cooperatively Breeding ◽  
Allocation Patterns

Population fluctuations of the African armyworm, Spodoptera exempta (Walker) (Lepidoptera: Noctuidae), in Outdoor Cages in Kenya

1981 ◽  
Vol 71 (2) ◽  
pp. 289-297 ◽  
Author(s):  
B. Persson
Keyword(s):  
Cynodon Dactylon ◽  
Lake Victoria ◽  
Larval Mortality ◽  
Adult Emergence ◽  
Developmental Time ◽  
Egg Laying ◽  
Spodoptera Exempta ◽  
Population Fluctuations ◽  
One Year ◽  
Nuclear Polyhedrosis

AbstractSpodoptera exempta (Wlk.) was reared for one year at three locations in Kenya: Msabaha on the coast, Nairobi, and Mbita Point on Lake Victoria. The potential yearly number of generations was 15·8 at Msabaha, 6·6 at Nairobi and 13·1 at Mbita Point. Average developmental time from egg deposition to adult emergence was 23·1, 54·9 and 27·8 days, respectively. The longest, 77·3 days, was recorded in Nairobi and the shortest, 19·4 days, at Msabaha. The survival rate varied little seasonally at the coast but was erratic inland, with some generations failing and others very successful. Larvae offered a choice of maize and stargrass (Cynodon dactylon) showed a preference for stargrass. Survival was higher on stargrass than on maize but the developmental time was longer. Mortality was highest in the larval stage. In all generations and at all locations, death was usually caused by a nuclear polyhedrosis virus. There was a positive relationship between larval mortality and rainfall, and a negative one between larval mortality and sunshine. Mating was restricted to after midnight. Females oviposited and then mated during the same night. Peak egg-laying took place before midnight, with a smaller peak at about 02·00–04·00 h.

Foraging trip strategies and habitat use during late pup rearing by lactating Australian fur seals

2011 ◽  
Vol 59 (4) ◽  
pp. 216 ◽  
Author(s):  
Roger Kirkwood ◽  
John P. Y. Arnould
Keyword(s):  
Habitat Use ◽  
Marine Mammal ◽  
Hot Spots ◽  
Marine Reserves ◽  
Central Place ◽  
Shelf Edge ◽  
Fur Seals ◽  
Eastern Australia ◽  
Management Perspective ◽  
Latitudinal Range

Australian fur seals (Arctocephalus pusillus doriferus) are the most conspicuous and abundant marine mammal in shelf waters of south-eastern Australia. To successfully rear offspring, the females must encounter sufficient prey on each foraging trip out of a central place for periods up to11 months each year. We investigated foraging trip strategies and habitat use by the females in three winter–spring periods, 2001–03, from four colonies that span the species’ latitudinal range and contribute 80% of pup production. Trip durations of 37 females averaged 6.1 ± 0.5 (s.e.) days, although >90% of the seal’s time at sea was spent <150 km travel (<2 days) away. Most females exhibited strong fidelities to individually preferred hot-spots. Females from colonies adjacent to productive shelf-edge waters generally had shorter trips, had smaller ranges, foraged closer to colonies and exhibited less diversity in trip strategies than did those from colonies more distant from a shelf-edge. From a management perspective, there was minimal overlap (<1%) between where females foraged and a system of marine reserves established in 2007, suggesting that habitats visited by lactating Australian fur seals currently receive minimal legislative protection.

Reproduction of Heterodontus portusjacksoni in Victoria, Australia: evidence of two populations and reproductive parameters for the eastern population

2007 ◽  
Vol 58 (10) ◽  
pp. 956 ◽  
Author(s):  
Javier Tovar-Ávila ◽  
Terence I. Walker ◽  
Robert W. Day
Keyword(s):  
Population Analysis ◽  
Sampling Bias ◽  
Early Spring ◽  
Egg Laying ◽  
Late Winter ◽  
Reproductive Parameters ◽  
Breeding Populations ◽  
Eastern Australia ◽  
Western Victoria ◽  
Far Eastern

Significant differences in the length–frequency composition of catch samples, mass–length relationships and length-at-maturity found between Heterodontus portusjacksoni from western and far-eastern Victoria, suggest the presence of at least two separate breeding populations off south-eastern Australia, with some mixing between these regions. In each region females attain a larger size than males, and collectively those sharks in western Victoria are smaller, present higher mass-at-length, and lower length-at-maturity than those in far-eastern Victoria. These regional differences might be a result of sampling bias, length-selective fishing mortality, environmental conditions, or genetic differences. However, tagging evidence from previous studies and the presence of two bio-geographic provinces in the region support the hypothesis of two separate breeding populations. The essential reproductive parameters for H. portusjacksoni population analysis in far-eastern Victoria were determined, using a novel method to estimate fecundity and the ovarian cycle of an egg-laying species. In this region, females have between 6 and 20 pre-ovulatory oocytes (average = 14, n = 29, standard deviation = 3.71) before the reproductive season. The species has an annual reproductive cycle correlated with water temperature, with ovulation starting during late winter to early spring and a ~6 month egg-laying period. The period from the onset of vitellogenesis to ovulation of oocytes is ~18 months.

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