Parental care in Sphaerium striatinum Lamarck: evidence for retention of competent offspring

2000 ◽  
Vol 78 (10) ◽  
pp. 1697-1701 ◽  
Author(s):  
Mark A Beekey ◽  
Ronald H Karlson ◽  
Alyse R Greenberg

The timing of offspring release is a fundamental turning point in the life history of any organism. It represents the end to many of the most costly forms of parental care (e.g., provisioning of nutrients for developing eggs and zygotes) and the beginning of an independent life for the offspring. Generally temporal variation in this event is attributed to a variety of physiological and evolutionary trade-offs. Here we examine the retention of offspring in the freshwater clam Sphaerium striatinum Lamarck. Brooded offspring are typically not released into the environment until they are 4.0 mm shell length (SL). We provide evidence that offspring as small as 2.0 mm SL are competent to process particles and produce both fecal and pseudofecal material. Furthermore, such small clams are shown to experience higher mortality than larger individuals once they are removed from brood pouches. Hence, the retention of competent offspring within brood pouches represents a form of extended parental care.

2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser

Biparental care systems are a valuable model to examine conflict, cooperation, and coordination between unrelated individuals, as the product of the interactions between the parents influences the fitness of both individuals. A common experimental technique for testing coordinated responses to changes in the costs of parental care is to temporarily handicap one parent, inducing a higher cost of providing care. However, dissimilarity in experimental designs of these studies has hindered interspecific comparisons of the patterns of cost distribution between parents and offspring. Here we apply a comparative experimental approach by handicapping a parent at nests of five bird species using the same experimental treatment. In some species, a decrease in care by a handicapped parent was compensated by its partner, while in others the increased costs of care were shunted to the offspring. Parental responses to an increased cost of care primarily depended on the total duration of care that offspring require. However, life history pace (i.e., adult survival and fecundity) did not influence parental decisions when faced with a higher cost of caring. Our study highlights that a greater attention to intergenerational trade-offs is warranted, particularly in species with a large burden of parental care. Moreover, we demonstrate that parental care decisions may be weighed more against physiological workload constraints than against future prospects of reproduction, supporting evidence that avian species may devote comparable amounts of energy into survival, regardless of life history strategy.


1992 ◽  
Vol 49 (10) ◽  
pp. 2196-2218 ◽  
Author(s):  
Kirk O. Winemiller ◽  
Kenneth A. Rose

Interspecific patterns of fish life histories were evaluated in relation to several theoretical models of life-history evolution. Data were gathered for 216 North American fish species (57 families) to explore relationships among variables and to ordinate species. Multivariate tests, performed on freshwater, marine, and combined data matrices, repeatedly identified a gradient associating later-maturing fishes with higher fecundity, small eggs, and few bouts of reproduction during a short spawning season and the opposite suite of traits with small fishes. A second strong gradient indicated positive associations between parental care, egg size, and extended breeding seasons. Phylogeny affected each variable, and some higher taxonomic groupings were associated with particular life-history strategies. High-fecundity characteristics tended to be associated with large species ranges in the marine environment. Age at maturation, adult growth rate, life span, and egg size positively correlated with anadromy. Parental care was inversely correlated with median latitude. A trilateral continuum based on essential trade-offs among three demographic variables predicts many of the correlations among life-history traits. This framework has implications for predicting population responses to diverse natural and anthropogenic disturbances and provides a basis for comparing responses of different species to the same disturbance.


2010 ◽  
Vol 176 (2) ◽  
pp. 212-226 ◽  
Author(s):  
James D. J. Gilbert ◽  
Andrea Manica

2017 ◽  
Vol 68 (9) ◽  
pp. 1771 ◽  
Author(s):  
Joanna G. Browne ◽  
Kylie A. Pitt ◽  
Mark D. Norman

Jellyfish form associations with a diverse fauna including parasites and commensals, yet, ecological data on these associations, particularly time series, are rare. The present study examined temporal variation in the intensities and prevalences of two symbionts, namely, a sphaeromatid isopod (Cymodoce gaimardii) and a parasitic anemone (Anemonactis clavus) of the scyphozoan jellyfish Catostylus mosaicus over a 2-year period. Jellyfish were captured from Port Phillip Bay, Victoria, Australia, approximately every 6 weeks and inspected for symbionts. The isopod occurred on C. mosaicus on 16 of the 19 sampling occasions; prevalences ranged from 5 to 85%, and were highest in summer and autumn. Intensity ranged from one to five isopods per jellyfish. Juvenile, immature and mature isopods were present. The parasitic anemone A. clavus occurred only between May and September. Prevalences were lower than for the isopod (on 5–20% of jellyfish when present) as was maximum intensity (two anemones per jellyfish). Catostylus mosaicus appears to play an important role in the life history of a suite of symbionts, and the present study is the first to examine temporal changes in the association of the jellyfish with two of these symbionts.


2017 ◽  
Vol 40 ◽  
Author(s):  
Bin-Bin Chen

AbstractThe mating-related evolutionary explanation that Maestripieri et al. offer does not apply to (1) infants' positive biases toward attractive individuals and (2) adults' positive biases toward attractive infants and children. They are best understood when integrated into an evolutionary life history framework. I argue that the life history of positive biases toward attractive individuals is driven by fundamental trade-offs made throughout development.


2016 ◽  
Vol 3 (12) ◽  
pp. 160740 ◽  
Author(s):  
Çağlar Akçay ◽  
Ádám Z. Lendvai ◽  
Mark Stanback ◽  
Mark Haussmann ◽  
Ignacio T. Moore ◽  
...  

Life-history theory predicts that optimal strategies of parental investment will depend on ecological and social factors, such as current brood value and offspring need. Parental care strategies are also likely to be mediated in part by the hypothalamic–pituitary–adrenal axis and glucocorticoid hormones. Here, we present an experiment in tree swallows ( Tachycineta bicolor ), a biparental songbird with wide geographical distribution, asking whether parental care is strategically adjusted in response to signals of offspring need and brood value and if so, whether glucocorticoids are involved in these adjustments. Using an automated playback system, we carried out playbacks of nestling begging calls specifically to females in two populations differing in their brood value: a northern population in Ontario, Canada (relatively higher brood value) and a southern population in North Carolina, USA (relatively lower brood value). We quantified female offspring provisioning rates before and during playbacks and plasma corticosterone levels (cort) once during late incubation and once immediately after playbacks. Females in both populations increased feeding rates temporarily during the first 2 h of playback but the increase was not sustained for the entire duration of playback (6 h). Cort levels from samples at the end of the playback did not differ between control females and females that received playbacks. However, females that had higher increases in cort between the incubation and nestling period had greater fledging success. These results suggest that females are able to strategically respond to offspring need, although the role of glucocorticoids in this strategic adjustment remains unclear.


2018 ◽  
Author(s):  
Dongjing Fu ◽  
Javier Ortega-Hernández ◽  
Allison C. Daley ◽  
Xingliang Zhang ◽  
Degan Shu

AbstractExtended parental care (XPC) is a complex reproductive strategy in which progenitors actively look after their offspring up to – or beyond – the first juvenile stage in order to maximize their fitness. Although the euarthropod fossil record has produced several examples of brood-care, the appearance of XPC within this phylum remains poorly constrained given the scarcity of developmental data for Palaeozoic stem-group representatives that would link juvenile and adult forms in an ontogenetic sequence. Here, we describe the post-embryonic growth of Fuxianhuia protensa from the early Cambrian Chengjiang Lagerstätte, and show parental care in this stem-group euarthropod. We recognize fifteen distinct ontogenetic stages based on the number and shape of the trunk tergites, and their allocation between the morphologically distinct thorax and abdomen. Our data demonstrate anamorphic post-embryonic development in F. protensa, in which tergites were sequentially added from a posterior growth zone. A life assemblage consisting of a sexually mature F. protensa adult alongside four ontogenetically coeval juveniles, constitutes the oldest occurrence of XPC in the panarthropod fossil record. These findings provide the most phylogenetically basal evidence of anamorphosis in the evolutionary history of total-group Euarthropoda, and reveal a complex post-embryonic reproductive ecology for its early representatives.


2016 ◽  
Author(s):  
Çağlar Akçay ◽  
Ádám Z. Lendvai ◽  
Mark Stanback ◽  
Mark Hausmann ◽  
Ignacio T. Moore ◽  
...  

AbstractLife history theory predicts that optimal strategies of parental investment will depend on ecological and social factors such as current brood value and offspring need. Parental care strategies are also likely to be mediated in part by the hypothalamic-pituitary-adrenal (HPA) axis and glucocorticoid hormones. Here we present an experiment in tree swallows (Tachycineta bicolor), a biparental songbird with wide geographic distribution, asking whether parental care is strategically adjusted in response to signals of offspring need and brood value and whether glucocorticoids are involved in these adjustments. Using an automated playback system, we carried out playbacks of nestling begging calls specifically to females in two populations differing in their brood value: a northern population in Ontario, Canada (relatively high brood value) and a southern population in North Carolina, USA (lower brood value). We quantified female offspring provisioning rates before and during playbacks and plasma corticosterone levels (cort) once during late incubation and once immediately after playbacks. Females in both populations increased feeding rates temporarily during the first two hours of playback but the increase was not sustained for the entire duration of playback (six hours). Cort levels from samples at the end of the playback did not differ between control females and females that received playbacks. However, females that had higher increases in cort between the incubation and nestling period had greater fledging success. These results suggest that females are able to strategically respond to offspring need, although the role of glucocorticoids in this strategic adjustment remains unclear.


2006 ◽  
Vol 63 (6) ◽  
pp. 995-1004 ◽  
Author(s):  
Gretta T. Pecl ◽  
Natalie A. Moltschaniwskyj

Abstract Many cephalopods continue growing while laying multiple egg batches over the adult life, with repro-somatic allocation continuing beyond attainment of reproductive maturity. Many species show extreme individual variation in reproductive investment. Factors driving this variation in adult Sepioteuthis australis were evaluated by examining allocation of energy to somatic and reproductive growth as a function of body shape, growth rate, maturation, and hatching season. Hatching season influence was sex-specific; males hatched in warmer months had greater reproductive investment, faster growth, and better somatic and reproductive condition, whereas females hatched in spring and summer had less reproductive investment. Seasonal impacts on life history resulted in an “alternation of generations”, with slow-growing squid in poor condition and with high levels of reproductive investment producing a generation with completely different life-history characteristics. This suggests that abiotic and biotic conditions that change seasonally could play a large role in determining energy allocated to reproduction. However, this was not driving trade-offs between size and number of offspring. Life-history trade-offs should be detectable as negative correlations between relevant traits. However, in Sepioteuthis australis there was little evidence of trade-offs between reproduction and growth or condition of individuals, suggesting a “live for today” lifestyle.


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