The effect of changing juvenile nutritional conditions and compensatory growth on life history traits in a field cricket, Gryllus texensis

An organism\u27s juvenile environment can significantly impact its adult phenotype. If an individual grows up in a resource-poor environment but the resource conditions improve, the organism can compensate for its reduced development. Although compensation is beneficial, the fast growth rate associated with it can be costly. To test for evidence of compensatory growth and its costs on adult traits, immunity, and reproduction in insects, I raised Gyllus texensis field crickets on either a good- or poor-quality diet, switched their diets half way through their juvenile period, and compared their growth rates. The poor-good quality diet should mimic compensatory growth. Once the crickets matured, I tested for effects of diet treatment on time to maturity, body mass, body size, and body condition. I also determined disease resistance of adult crickets by monitoring their survival after an injection with the bacteria Serratia marcescens. After each cricket died, I measured their reproductive investment to determine any costs associated with improving juvenile nutritional conditions. Even though I did not find any evidence of compensatory growth in my experimental crickets, diet treatment did have an effect on adult life history traits and reproductive investment. Crickets on the improving diet treatment took significantly longer to mature than good-good quality diet crickets, and were lighter, smaller and in poorer body condition than the crickets on the good-good quality diet. Despite negative effects of an improving juvenile diet on adult traits, there was no effect on reproductive investment or disease resistance. Lack of reproductive and immunity differences between the good-good quality and poor-good quality diet crickets suggests that they were able to compensate for their period of poor nutrition through increasing investment in reproduction and immunity over body size and body condition. My results imply that crickets might be more resilient to fluctuations in resource conditions than organisms in other taxa

The Santa Maria: Baltimore Privateering and Piracy during the Latin American Revolutions

After the War of 1812 and the Napoleonic Wars, South American privateering in Baltimore took on a new dimension. Technically, the United States remained neutral with Spain in the face of Latin American revolution. However, Baltimore remained an area where privateering on foreign commissions was common. This paper puts privateering in 1817 in the context of international and national affairs. The Santa Maria involved pirates and what was considered a bona fide purchaser in a prize court. Included in the paper are historical backgrounds of the key players involved as well as a legal analysis of the issues brought up in The Santa Maria and related cases

Latitudinal patterns and environmental drivers of taxonomic, functional, and phylogenetic diversity of woody plants in western Amazonian terra firme forests

Elucidating how environmental factors drive plant species distributions and how they affect latitudinal diversity gradients, remain essential questions in ecology and biogeography. In this study we aimed: 1) to investigate the relationships between all three diversity attributes, i.e., taxonomic diversity (TD), functional diversity (FD), and phylogenetic diversity (PD); 2) to quantify the latitudinal variation in these diversity attributes in western Amazonian terra firme forests; and 3) to understand how climatic and edaphic drivers contribute to explaining diversity patterns. We inventoried ca. 15,000 individuals from ca. 1,250 species, and obtained functional trait records for ca. 5,000 woody plant individuals in 50 plots of 0.1 ha located in five terra firme forest sites spread over a latitudinal gradient of 1200 km covering ca. 10°C in latitude in western Amazonia. We calculated all three diversity attributes using Hill numbers: q = 0 (richness), q = 1 (richness weighted by relative abundance), and q = 2 (richness weighted by dominance). Generalized linear mixed models were constructed for each diversity attribute to test the effects of different uncorrelated environmental predictors comprising the temperature seasonality, annual precipitation, soil pH and soil bulk density, as well as accounting for the effect of spatial autocorrelation, i.e., plots aggregated within sites. We confirmed that TD (q = 0, q = 1, and q = 2), FD (q = 0, q = 1, and q = 2), and PD (q = 0) increased monotonically towards the Equator following the latitudinal diversity gradient. The importance of rare species could explain the lack of a pattern for PD (q = 1 and q = 2). Temperature seasonality, which was highly correlated with latitude, and annual precipitation were the main environmental drivers of variations in TD, FD, and PD. All three diversity attributes increased with lower temperature seasonality, higher annual precipitation, and lower soil pH. We confirmed the existence of latitudinal diversity gradients for TD, FD, and PD in hyperdiverse Amazonian terra firme forests. Our results agree well with the predictions of the environmental filtering principle and the favourability hypothesis, even acting in a 10°C latitudinal range within tropical climate

TAZRAWT TALƔAWIT D TESNAMKIT N WAWALEN IMEYNUTEN N WUNGAL “ARRAC N TEFSUT” N YUSEF UBELLIL

30cm; 53p

The effect of changing juvenile nutritional conditions and compensatory growth on life history traits in a field cricket, Gryllus texensis

An organism's juvenile environment can significantly impact its adult phenotype. If an individual grows up in a resource-poor environment but the resource conditions improve, the organism can compensate for its reduced development. Although compensation is beneficial, the fast growth rate associated with it can be costly. To test for evidence of compensatory growth and its costs on adult traits, immunity, and reproduction in insects, I raised Gyllus texensis field crickets on either a good- or poor-quality diet, switched their diets half way through their juvenile period, and compared their growth rates. The poor-good quality diet should mimic compensatory growth. Once the crickets matured, I tested for effects of diet treatment on time to maturity, body mass, body size, and body condition. I also determined disease resistance of adult crickets by monitoring their survival after an injection with the bacteria Serratia marcescens. After each cricket died, I measured their reproductive investment to determine any costs associated with improving juvenile nutritional conditions. Even though I did not find any evidence of compensatory growth in my experimental crickets, diet treatment did have an effect on adult life history traits and reproductive investment. Crickets on the improving diet treatment took significantly longer to mature than good-good quality diet crickets, and were lighter, smaller and in poorer body condition than the crickets on the good-good quality diet. Despite negative effects of an improving juvenile diet on adult traits, there was no effect on reproductive investment or disease resistance. Lack of reproductive and immunity differences between the good-good quality and poor-good quality diet crickets suggests that they were able to compensate for their period of poor nutrition through increasing investment in reproduction and immunity over body size and body condition. My results imply that crickets might be more resilient to fluctuations in resource conditions than organisms in other taxa.</p