Weygoldt (1980) Complex brood care and reproductive behaviour in captive poison-arrow frogs, Dendrobates pumilio O. Schmidt. Behav. Ecol. Sociobiol., 7:329-332
Brood care in Dendrobates pumilio not only involves egg attendance and tadpole transport, but also tadpole attendance and feeding. Each tadpole is carried by the attending female to a water-filled bromelial leaf axil and regularly fed on unfertilized eggs. The tadpole responds to an approaching adult with a specialized, conspicuous behavior signalling its presence. Male-male competition includes fighting, egg eating, and male tadpole transport. D. pumilio is the first frog known to feed its free-living larvae.
Shaffer & Formanowicz Jr (1996) A cost of viviparity and parental care in scorpions: reduced sprint speed and behavioural compensation. Animal Behaviour, 51:1017-1024
Current reproductive effort may often be at the expense of future reproduction. One way in which future reproduction of viviparous animals may be affected is by increased risk of predation resulting from decreased mobility associated with pregnancy. The common striped scorpion,Centruroides vittatus, may experience considerable risk of predation associated with reproduction because it is viviparous, with an eight-month gestation period.C. vittatusalso carries the newborn young on its back during their first instar. The purpose of this study was to establish a cost of viviparity and parental care in these scorpions by determining sprint speed at three reproductive stages: pregnant, carrying offspring and post-dispersal of offspring. Post-dispersal speed was used as a best estimate of non-pregnant speed. Pregnant speeds averaged 84% of post-dispersal speeds. Lower speeds were correlated with absolute and relative measures of litter size. Speed while carrying offspring averaged 61% of post-dispersal speed, and was correlated with mass of the litter and number of individuals in the litter. Sixty-five per cent of the females carrying young could not be induced to run; these females instead assumed a defensive posture. Results indicate that female scorpions experience a cost (in decreased running speed) to viviparity and parental care, and that some females may reduce this cost by using an alternative defensive strategy.
Hayward, Mar, Lahdenperä & Lummaa (2014) Early reproductive investment, senescence and lifetime reproductive success in female Asian elephants. Journal of Evolutionary Biology (IN PRESS)
The evolutionary theory of senescence posits that as the probability of extrinsic mortality increases with age, selection should favour early-life over late-life reproduction. Studies on natural vertebrate populations show early reproduction may impair later-life performance, but the consequences for lifetime fitness have rarely been determined, and little is known of whether similar patterns apply to mammals which typically live for several decades. We used a longitudinal dataset on Asian elephants (Elephas maximus) to investigate associations between early-life reproduction and female age-specific survival, fecundity and offspring survival to independence, as well as lifetime breeding success (lifetime number of calves produced). Females showed low fecundity following sexual maturity, followed by a rapid increase to a peak at age 19 and a subsequent decline. High early life reproductive output (before the peak of performance) was positively associated with subsequent age-specific fecundity and offspring survival, but significantly impaired a female's own later-life survival. Despite the negative effects of early reproduction on late-life survival, early reproduction is under positive selection through a positive association with lifetime breeding success. Our results suggest a trade-off between early reproduction and later survival which is maintained by strong selection for high early fecundity, and thus support the prediction from life history theory that high investment in reproductive success in early life is favoured by selection through lifetime fitness despite costs to later-life survival. That maternal survival in elephants depends on previous reproductive investment also has implications for the success of (semi-)captive breeding programmes of this endangered species.
Mas, Haynes & Kölliker (2009) A chemical signal of offspring quality affects maternal care in a social insect. Proc. R. Soc. Lond. B., 276:2847-2853
Begging signals of offspring are condition-dependent cues that are usually predicted to display information about the short-term need (i.e. hunger) to which parents respond by allocating more food. However, recent models and experiments have revealed that parents, depending on the species and context, may respond to signals of quality (i.e. offspring reproductive value) rather than need. Despite the critical importance of this distinction for life history and conflict resolution theory, there is still limited knowledge of alternative functions of offspring signals. In this study, we investigated the communication between offspring and caring females of the common earwig,Forficula auricularia, hypothesizing that offspring chemical cues display information about nutritional condition to which females respond in terms of maternal food provisioning. Consistent with the prediction for a signal of quality we found that mothers exposed to chemical cues from well-fed nymphs foraged significantly more and allocated food to more nymphs compared with females exposed to solvent (control) or chemical cues from poorly fed nymphs. Chemical analysis revealed significant differences in the relative quantities of specific cuticular hydrocarbon compounds between treatments. To our knowledge, this study demonstrates for the first time that an offspring chemical signal reflects nutritional quality and influences maternal care.
I love the Surinam toad, it has such a weird reproductive biology. The eggs are laid on the female's back and then implant themselves into her skin. The baby toads then pop out of the females skins, crazy.
Rabb & Snedigar (1960) Observations on Breeding and Development of the Surinam Toad, Pipa pipa. Copeia, 1:40-44
“Unfortunately we did not see the actual deposition of eggs. Bartlett (1896) reported that an evagination of the cloaca is used to conduct the eggs onto the female's back. The figure he furnished of this "ovipositor" was drawn from a specimen that had died while laying, and the structure illustrated was probably pathological. Barlett's specimen is not extant, although it was sent to Boulenger for examination (Sclater, 1896). We wish to thank Alice G. C. Grandison, who kindly searched for it at the British Museum and the Zoological Society of London.”
“The young were noticeably active on, but it was not until day 77 th young emerged. The only previous incubation period, 82 days, seems to the report of Fermin (1765). The second emergence was: day 77, three; 90, one; 120, one; 134, one; 135, four; nine. Of these 20 live young, three (including the only grossly abnormal one) died within 10 days after emerging. Partial shedding by the female took place at the onset of the last emergences (day 134).”