Paper Title
Darwin’s Hypothesis and Rensch’s Rule to assess the Effectiveness of the Reproductive Strategy of two Congeneric Forest Moths

Abstract
Body size of Thaumetopoea species correlates with several factors such as reproductive fitness, environmental changes and the quality and quantity of food during critical development stages. For reproductive efficiency considerations, sexual size dimorphism (SSD), which happens to be widespread among animal taxa, defines often different optimal body size for males and females. For the Palearctic pine moths of the genus Thaumetopoea in Algeria, larvae of T. pityocampa feed during winter while larvae of its congeneric T. bonjeani develop during summer although they both feed upon Atlas cedar Cedrus atlantica. This discrepancy in ecological behavior leads to different reproductive strategies based on parameters related to egg batch length, number of eggs per batch, eggs protection mechanisms and female body size. According to Darwin’s fecundity advantage hypothesis (1871), large-sized female body influences positively the reproductive fitness as their fecundity is supposedly higher. The universal allometry scaling phenomenon rule proposed by Rensch (1950) states that degree of SSD tends to decrease with increasing of body size in female-biased taxa. Here, we propose two morphometrical parameters; scale surface and body surface estimated from basic measurements. We also perform bio-morphometrical comparisons involving two sympatric forest pests to evaluate the degree of intra-specific SSD and its effectiveness in the reproductive strategy. We also discuss Darwin’s hypothesis through investigation of correlations between body size and fecundity parameters. Rensch’s rule is checked for consistency in the Thaumetopoea genus. Results highlight a female-biased SSD in both species. The cryptic relationships between female body size and fecundity shown in this study provide a weak support to Darwin’s hypothesis. Intrageneric test allowed saying that Rensch’s rule does not hold in our species. Finally, will one of the two species have advantage over the other if the ecological behavior of one of them is changed in the context of global climate change? Keywords - Thaumetopoea, Cedrus Atlantica, Sexual Size Dimorphism, Darwin’s Hypothesis, Rensch’s Rule.