Statistical analysis of occupancy rates for overdispersed populations by redistribution procedures: Application to the european corn borer EGG masses distribution

Standard statistical analyses of distributions of individuals from contingency tables are generally invalid if the individuals are not distributed independently of each other. In this paper, we discuss a method of testing hypotheses about classification category occupancy rates for overdispersed population or for population whose individuals are distributed by groups rather than lonely. These methods are based on population redistribution simulations and provide valid, exact and powerful tests in situations for which classical methods are not appropriate. Illustrations are given from the European Corn Borer eggs data.     

Comparison of physicochemical properties of pollen substitute diet for honey bee (Apis mellifera)

Apis mellifera L., a globally important pollinator, is crucial in the maintenance of its colonies due to a variety of stresses. Healthy nutrition is believed to help grow their population and relieve the stressors. We used our-prepared and commercial diets, and the nutrition contents were then analyzed for free sugar, organic acids, free amino acids, inorganic ions, total polyphenols, vitamin C, and the pH. The total free sugar, organic contents, free amino acids, inorganic ions, and total polyphenols were in the range of 228.59 to 661.00, 0.91 to 20.60, 6.52 to 24.36, 10.25 to 27.61, and 1.65 to 10.17 mg/g, respectively. The highest contents of free sugar, organic acids, free amino acids, inorganic ions, and total polyphenols were found in YBNH (661 mg/g), Megabee (20.60 mg/g), Beebread (24.36 mg/g), AIGT + Soytide (27.61 mg/g), and Beebread (10.17 mg/g), respectively. The pH values were maintained at 4.45 to 5.70 among all ten samples. Group I showed the same level of total free sugars (Group II and Group IV), organic acids (Group II), inorganic ions (Group II, Group III, and Group IV), polyphenols (Group II), and pH (Group IV). For the total free amino acids, Group I showed a significantly higher (P < 0.05) level than that of Group II and Group III. Group I had a comparable nutrition content to the commercial bee diet but had a higher total free amino acid content. High levels of inorganic ions, free amino acids, and organic acids were found in the AIGT + Soytide.     

Simple rules based on pile slope are used in the self organization of sand pile formation by <Emphasis Type="Italic">Pheidole oxyops</Emphasis> ants

We tested the hypothesis that slope influences where worker ants deposit excavated soil on piles near the nest entrance. We predicted that ants will deposit their load near the top of a pile where the slope changes from upward to downward, to prevent material rolling back towards the entrance. We tested this hypothesis by studying five natural colonies of Pheidole oxyops ants at a field site at S?o Sim?o, Brazil. At this site, each colony was dumping sandy soil excavated from its underground nest in a crescent-shaped pile c. 13 cm from and perpendicular to the nest entrance. Each nest was given an experimental sand pile of symmetrical curved cross section on a plywood platform that could be tilted 15 degrees up or down. From videos, the locations where individual ants dumped their soil loads were measured in relation to the inner (position = 0) and outer (position = 1) edges of the pile. When the platform was tilted down the ants deposited their loads significantly closer to the inner edge (0.458 ± 0.007) than when not tilted (0.530 ± 0.006). When the platform was tilted up the ants deposited their loads significantly further from the inner edge (0.626 ± 0.006) than when not tilted (0.522 ± 0.006). These results support the hypothesis that ants use pile slope in deciding where to dump their load. A similar rule is probably used in other ant species that place excavated soil in steep piles near the nest entrance. Received 5 February 2007; revised 10 June 2007; accepted 9 October 2007.