Body Mass Growth Rate Research Articles

Effects of Inbreeding on Skeletal Size and Fluctuating Asymmetry of Peromyscus polionotus Mice

Measurements of size and asymmetry in morphology might provide early indications of damaging effects of inbreeding or other genetic changes in conservation breeding programs. We examined the effects of inbreeding on size and fluctuating asymmetry (FA) in skull and limb bone measurements in experimental populations of three subspecies of Peromyscus polionotus mice that had previously been shown to suffer significant reductions in reproductive success when inbred. Inbreeding caused significant depression in mean size in two of the subspecies (P. p. rhoadsi and P. p. subgriseus), but the effects were smaller in the third (P. p. leucocephalus). Inbreeding caused an increase in FA of just one of eight bilateral traits in one subspecies (P. p. rhoadsi). Inbreeding depression in size was more easily detected than the effects of inbreeding on FA. FA may be much less sensitive to inbreeding and other stresses than are more direct measures of fitness such as reproductive output and body mass growth rate. Given the large sample sizes and statistical complexity required to assess changes to typically very small levels of FA in captive populations, FA will not likely provide a useful measure of inbreeding depression in captive populations.

Are stag beetles fungivorous?

Stag beetle larvae generally feed on decaying wood; however, it was unknown whether they can use wood-rotting fungi alone as food. Here, to clarify this, newly hatched larvae of Dorcus rectus (Motschulsky) (Coleoptera: Lucanidae) were reared for 14 days on artificial diets containing a fixed amount of freeze-dried mycelia of the following fungi: Bjerkandera adusta, Trametes versicolor, Pleurotus ostreatus, and Fomitopsis pinicola. The mean incremental gain in larval body mass was greatest on diets containing B. adusta, followed by T. versicolor, P. ostreatus, and F. pinicola. The growth rate of body mass correlated positively with mycelial nitrogen content of the different fungi. It also correlated positively with the mycelial content of B. adusta in the diet. Addition of antibiotics to diets with mycelia nearly halved larval growth, indicating that larvae were able to use fungal mycelia as food without the assistance of associated microbes although the microbes positively affected larval growth. Four newly hatched larvae reared on artificial diets containing B. adusta mycelia developed to the second instar in 21–34 days; and one developed to the third (=final) instar. This study provides evidence that fungi may constitute the bulk of the diet of D. rectus larvae.

Atmospheric hypoxia constrains skeletal growth and alters bone microstructure in hatchlings of the American alligator (Alligator mississippiensis)

Skeletal growth reflects whole‐body growth of the animal, and features of bone microstructure (vascular density, collagen arrangement) can be used to infer an animal's growth strategy. This relationship, however, may be altered by environmental change. Vertebrates are known to have endured large‐scale fluctuations in atmospheric %O2 during their evolutionary history, but no study to date has tested the effect of atmospheric %O2 on skeletal growth. We reared hatchlings of the American alligator under chronic hypoxia (12%O2), normoxia (21%O2) and hyperoxia (30%O2). Animals were fed ad libitum every other day, and received injections of fluorescent dyes to determine bone deposition rates. The femoral midshaft shows no significant difference in bone formation rates (BFR) between normoxic and hyperoxic alligators, and an identical correlation with body mass growth rate (GRMb). Hypoxic animals, however, show a significantly higher ratio of BFR:GRMb, which results in a relatively robust skeleton. This is surprising, since hypoxia is thought to impair collagen and mineral deposition in new bone. We argue that any inference of growth rates of extinct vertebrates based on their bone microstructure (e.g., on the amount of bone deposited between seasonal growth rings) should take into account the prevalent atmospheric %O2 contemporary for the species. Funded by NSF IOB 04445680 to JWH. TO supported by NIH 2T32AR047752.

Growth Rate and Fecundity of Bleak (Alburnus Alburnus (L.) in the Sand-Pit Lake Chepintsi (Bulgaria)

ABSTRACTThe population status of bleak (Alburnus alburnut (L.) in sand-pit lake Chepintsi near Sofia by using some biological factors as growth rate, condition and fecundity was investigated. The maximum age, length and body mass of bleak were 3 years, 12.7 mm and 20 g, respectively. The first, second and third age group were 5.77%, 63.46%, 30.77% respectively. The linear and body mass growth rate were described by the equations: SL=1.3487+2.6601R (r=0.88); W=0.1499L1.8499 (r=0.95), respectively. The condition coefficient of bleak (k) was the lower than that for other populations from different water bodies. Also the populations from different water basins were compared by the body mass at the same length. Fecundity was 7 168 eggs, the average was 1 707–12 284 eggs. The fecundity-length and fecundity-weight relationship were described by the equations: F=387.32L+4365.7 (r=0.46); F=1368.4W-3151.9 (r=0.59) respectively.

Growth and its relationship to fledging success of African black oystercatcher Haematopus moquini chicks

We investigated the growth of African black oystercatcher Haematopus moquini chicks on Robben Island, South Africa, over three austral summers, 2001–2004. Using a robust regression analysis to determine the growth parameters of chicks of known and unknown age we found that oystercatchers from our study population had a Gompertz growth rate coefficient that was 2% less than predicted for body mass based on the equation for waders. Leg growth lagged initially, then increased and slowed again as the chicks became older, whereas wing growth was slow initially but increased with age. Chicks with small growth rate coefficients for body mass exhibited retarded growth of all body measures except wing length. This enabled these chicks to fledge in a shorter period of time than their slow growth would otherwise allow. The growth rate of body mass was observed to vary greatly between chicks. Fast-growing African black oystercatchers had a shorter pre-fledging period; were larger at fledging and were more likely to fledge successfully. African black oystercatchers display sibling rivalry, and once a dominance relationship is established, the larger chick remains so during the pre-fledging period. Larger siblings fledged earlier and at a heavier mass than the smaller siblings and this may improve their chances of survival. Neither hatching date nor brood size influenced the growth rate coefficients.

Assessing Growth and Age of Whiskered TernChlidonias hybridaChicks using Biometrics

The growth of Whiskered Tern Chlidonias hybrida chicks was investigated in Lake Grand-Lieu, western France. Body mass, tarsus, culmen and wing lengths of 33 chicks from 19 nests held in enclosures were measured at intervals of 2–3 days during the rearing period (0–20 days). The repeatability between two observers in chick body size measurements was generally high (overall 0.94), with the highest value for the wing length. Tarsus length and body mass increased fast and reached asymptotic values at about 14 (23.23 mm ± 0.18 SE) and 16 days (92.35 g ± 1.82 SE). The body mass growth rate (K, resulting from a logistic model) was 0.294 g day-1 ± 0.016. The linear growth rate at age 3–9 days was 6.32 g day-1 ± 0.28 SE. The standardized linear growth rate was 7.0% of adult body mass, which was in the range of values recorded for the closely related Black Tern Chlidonias niger (6.5–7.9%). The culmen and wing were still growing at fledging (age 20 days), asymptotic values had clearly not been reached. Before fledgi...

Relationships between bone growth rate, body mass and resting metabolic rate in growing amniotes: a phylogenetic approach

We explored the factors that explain the variation in resting metabolic rates (RMR) in growing amniotes by using the phylogenetic comparative method. For this, we measured raw RMR (mL O2 h−1), body mass, body mass growth rate, and periosteal bone growth rate in a sample of 44 growing individuals belonging to 13 species of amniotes. We performed variation partitioning analyses, which showed that phylogeny explains a significant fraction of the variation of mass-specific RMR (mL O2 h−1 g−1), and that the cost of growth is much higher than the cost of maintenance. Moreover, we tested the hypothesis of the independence of energy allocation, and found that maintenance metabolism and growth rates are not significantly related. Finally, we calculated the statistical parameters of the relationship between geometry-corrected RMR (mL O2 h−1 g−0.67) and bone growth rate. This relationship could potentially be used in palaeobiology to infer RMR from bone tissue samples of fossil species by assuming Amprino’s rule (according to which bone tissue types reflect bone growth rates). These estimates would be especially interesting for Mesozoic non-avian theropod dinosaurs and Permian and Triassic therapsids to investigate, respectively, the origin of avian and mammalian endothermy. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 92, 63–76.

Postnatal growth in the Lesser Mouse-eared bat, Myotis blythii, in captivity

Postnatal growth of body mass, forearm and the epiphyseal phalangeal gap was studied in three Lesser Mouse-eared bats, Myotis blythii, which were born and reared in a flight cage. The pups at birth had a mean birth body mass of 7.4 g and forearm length of 26.0 mm. At 64 days, mean body mass had reached 94.4% of adult mass (29.3 g) and mean forearm length was 96.1% of adult length (58.6 mm). The length of forearm and body mass increased linearly during the first 3 weeks, and thereafter maintained an apparent stability. The epiphyseal gap of the fourth metacarpal-phalangeal joint increased until 16 days, then decreased linearly until 52 days and thereafter fused. The rate of body mass gain and forearm growth during the first 24 days was 0.8 g/day and 1.32 mm/day respectively. Both asymptotic size of body mass and forearm together with the growth rate of body mass were higher in the captive bats. However, the growth rate of forearm and the rate of closure of the epiphyseal gap in the free-living population were slightly less than in the captive individuals.

Maternal compensation for hatching asynchrony in the collared flycatcherFicedula albicollis

Several hypotheses have been proposed to explain the adaptiveness of hatching asynchrony for the parents, but delayed hatching is generally detrimental for the late hatched young. These offspring often experience competitive disadvantage and delayed development. If hatching asynchrony has a reason other than producing competitive differences among offspring, it would be advantageous, not only for the offspring but even for the parents, to compensate for its detrimental effects. In some species, increasing investment into later laid eggs has been reported and discussed as a compensation mechanism, but its effect on nestling growth and fledging size has not been examined in details. In this study we investigated nestling growth and size at fledging in terms of body mass and length of primaries in relation to the accurate laying and hatching order in collared flycatcherFicedula albicollisbroods. We found that females laid larger eggs at the end of the laying sequence, and this helped to decrease the disadvantages for the last offspring. The last offspring had lower body mass growth rate and fledged with shorter feathers, but in both cases the larger the last egg was, the smaller the lag of the offspring was. We conclude, that even if females were not able to fully compensate for the detrimental effects of hatching asynchrony, larger eggs may improve the survival prospects of late hatched nestlings.

Comparison of Two Artificial Ultraviolet Light Sources used for Chuckwalla, Sauromalus obesus, Husbandry

ABSTRACT Two studies were conducted to determine the suitability of the Westron Corp. self-ballasted mercury vapor lamps in the captive maintenance of the chuckwalla lizard, Sauromalus obesus. Initially, preference for basking under either a Westron lamp or an incandescent flood lamp was measured in a separate enclosure involving five individuals selected from a group of eight juveniles. Following this, the eight chuckwallas were divided into two groups and maintained for fifteen months in indoor enclosures illuminated with either an incandescent flood lamp and fluorescent Sylvania 350 BL combination or a single Westron self-ballasted mercury vapor lamp. Snout-to-vent length (SVL), body mass, and cloacal body temperatures were measured every two weeks. After nine months, the lizards were radiographed to assess bone density and blood was collected for assay of 25-hydroxyvitamin D. No significant differences in SVL and body mass growth rates, cloacal body temperatures or bone densities were observed between...