New World Monkeys and Color

The visual worlds of most primates are rich with potential color signals, and many representatives of the order have evolved the biological mechanisms that allow them to exploit these sources of information. Unlike the catarrhines, platyrrhines typically have sex-linked polymorphic color vision that provides individuals with any of several distinct types of color vision, including both trichromatic and dichromatic variants. In recent years, this polymorphism has been the target of an expanding range of research efforts. As a result, researchers now reasonably understand the proximate biology underlying the polymorphisms, and a number of ideas have emerged as to their evolution. Progress has also been made in illuminating how color vision capacities may be related to the particular visual tasks that New World monkeys face.     

An Ethnoarchaeological Study of Mobility, Architectural Investment, and Food Sharing among Madagascar's Mikea

Ethnoarchaeology is a field of study that aims to provide the information needed to draw reliable behavioral inferences from archaeological data. In this study, data from four settlement types (permanent villages, forest hamlets, seasonal hamlets, and foraging camps) of a forager–farmer population in southwestern Madagascar are examined from an archaeological perspective. Doing so shows that house size, house post diameter variability, outdoor workspace, trash disposal, and feature diversity jointly sort out settlements of different lengths of occupation. However, the relationship between mobility and material culture is not simply a product of the length of stay; it is also affected by differences in the social environments of settlements of different occupational lengths. Using the behavioral ecology of food sharing, we show that certain architectural changes that ensure privacy are expected to occur as settlements become larger and more permanent. These observations from Madagascar should be applicable to other areas.     

Testing the Metabolic Scaling Theory of tree growth

1.  Metabolic Scaling Theory (MST) predicts a 'universal scaling law' of tree growth. Proponents claim that MST has strong empirical support: the size-dependent growth curves of 40 out of 45 species in a Costa Rican forest have scaling exponents indistinguishable from the MST prediction.
2.  Here, we show that the Costa Rican study has been misinterpreted. Using Standardized Major Axis (SMA) line-fitting to estimate scaling exponents, we find that four out of five species represented by more than 100 stems have scaling exponents that deviate significantly from the MST prediction. On the other hand, sample sizes were too small to make strong inferences in the cases of 33 species represented by fewer than 50 stems.
3.  Recently, it has been argued that MST is useful for predicting average scaling exponents, even if individual species do not conform to the theory. We find that the mean scaling exponent of the Costa Rican trees is greater than predicted (across-species mean  =  0.44), and hypothesize that scaling exponents in natural forests will generally be greater than predicted, because the theory fails to model asymmetric competition for light.
4.   Synthesis . We highlight shortcomings in the interpretation of data used in support of a key MST prediction. We recommend that future research into biological scaling should compare the merits of alternative models rather than focusing attention on tests of a single theory.     

Female-specific color is a signal of quality in the striped plateau lizard (Sceloporus virgatus)

Recent theoretical and empirical studies confirm that male matechoice and/or female–female mate competition can be expressedin the absence of sex-role reversal. Such reproductive patternsmay select for the evolution of female traits that indicatefemale phenotypic or genotypic quality among non–role-reversedspecies. Although attention to the evolution and function offemale ornaments is increasing, additional focus is needed onfemale-specific ornaments (those not expressed in conspecificmales) and on nonavian systems in order to gain a broad understandingof how selection acts directly on ornamentation of female animals.In the striped plateau lizard, Sceloporus virgatus, only femalesdevelop orange throat patches during the reproductive season.The color peaks in expression near the time of ovulation andappears to stimulate male courtship. Here, I examine whetherthis female-specific ornament can be used by males to reliablyassess female phenotypic quality. Using multivariate regressionanalyses, I show that the area of the orange color patch predictsbody condition and mite load, the chroma (i.e., saturation)of the color patch predicts body size, and both patch area andchroma reliably predict average egg mass. Thus, female reproductivecolor may function as a condition-dependent signal, indicatingphenotypic quality to potential mates.     

An Experimental study of reduced parental effort and future reproductive success in the puffin, Fratercula arctica

1. The puffin, a long-lived seabird, was studied on the Isle of May, East Scotland between 1990 and 1992. During two of these years, parental effort was experimentally decreased by supplementary feeding of young. This aimed to identify inter-year reproductive costs, and show whether they took the form of reduced adult survival, reduced fledging success and/or a reduction in the 'quality' of offspring in the following year.
2. The feeding treatment significantly reduced the daily number of feeds delivered by experimental parents by 67% in 1990 and 87% in 1991.
3. The proportions of experimental and control parents returning to the colony in the year following manipulation did not differ significantly, although in 1991, 2·5 times as many controls (young unfed) as experimental birds (young fed) failed to return.
4. The fledging success of experimental pairs in the year following manipulation (68%) was significantly higher than that of controls (24%).
5. Experimental pairs raised young with significantly higher body condition (Residual Peak Mass) than that of controls in the year following manipulation (1992).
6. Experimental parents did not differ from controls in their body condition (Lipid Reserve Mass) or rate of reserve depletion, either in the year of manipulation or in the following breeding season; hence there was no evidence for a role of the measured component of body condition in the cost mechanism.
7. The study demonstrated inter-year reproductive costs for puffins and supported the hypothesis that long-lived species reduce the 'quality' of their offspring or abandon a breeding attempt rather than compromise their survival and future opportunities to reproduce.     

Morphology of the female reproductive organs of the African lion (Panthera leo)

The topography and splanchnology of the reproductive organs of the African lioness were studied and described in situ and after removal. The kidneys were located far caudally in relation to the thirteenth ribs. The suspensory ligament was very well developed, originated in a fan‐like manner from the dorsolateral abdominal wall lateral to the kidney and extended up to a few centimetres cranial to the kidney. The proper ligament of the ovary as well as the round ligament was well developed. The round ligament inserted on the medial femoral fascia. The left ovary was bigger than the right. The ovarian bursa had a short mesosalpinx that did not cover any part of the ovary and the fimbriae extended along the entire length. The urethral tuberculum as well as the urethral crest were well developed. The left uterine horn was longer than the right. The uterine tube was found to open directly into the tip of the uterine horn and not onto a papilla. The reproductive organs of the lioness resembled those of the domestic cat and dog but with some major differences.     

Food and water deprivation effects on reproduction in female Blattella germanica

The effects of food and water deprivation on survival and reproduction of adult female German cockroaches were examined. Females, maintained under constant conditions, were deprived of food or water following adult maturation, mating, during the oothecal incubation period, and after first oothecal hatch. It was found that both food and water deprivations caused increased mortality, delays in the reproductive cycle and decreased oothecal hatch. The relative importance of food vs. water deprivation on reproduction is discussed along with possible reproductive strategies for this species.

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Résumé Les femelles, maintenues en conditions constantes, ont été privées d'aliments et d'eau après la maturité imaginale, l'accouplement, pendant la période d'incubation et après l'éclosion de la première oothèque. On a observé une mortalité accure, un retard dans le cycle de reproduction et une diminution des éclosions de l'oothèque. L'importance relative de l'alimentation par rapport au jeûne hydrique sur la reproduction est discutée en relation avec les stratégies reproductives possibles de cette espèce.