The Hemiptera order has 23,000 species that are distributed among many families. Two of these are the Pentatomidae and Reduviidae families. The aim of this study was to identify the different species of insects from the Reduviidae and Pentatomidae families as well as each species’ abundance in three ecological niches (forest, forest edge, and farm land). The study was conducted in six communities of Los Yungas, La Paz (Carmen Pampa, San Pablo, San Juan de la Miel, Altuspata, Choro Alto, and Choro). In each community, three Malaise traps were installed in the three ecological niches (forest, forest edge, and farm land). The six communities were evaluated for a period of one year. The work was divided among four groups due to the fact that two families were being studied in two different municipalities. In the Coroico municipality (Carmen Pampa, San Pablo, and San Juan de la Miel), the study took place from May 2006 to May 2007. In the Coripata municipality (Altuspata, Choro Alto, and Choro), the study took place from May 2007 to May 2008. The first group identified 34 morphospecies of the Pentatomidae family with 137 individuals in the Carmen Pampa, San Pablo, and San Juan de la Miel communities. The second group identified 19 species of the Pentatomidae family with 54 individuals in the Altuspata, Choro Alto, and Choro communities. The third group found 31 species of the Reduviidae family along with 77 individuals. The fourth group identified 14 species of the Reduviidae family along with 60 individuals. Carmen Pampa and San Juan de la Miel are similar in terms of plant life and climate. San Pablo, however, is different due to its much drier climate. Morphospecies number three from the Pentatomidae family was the most abundant in the farm land niche in San Juan de la Miel. In all six communities, we found that morphospecies 16 was the most abundant in the forest niche. In addition, we found that there is little similarity between the species that inhabit both the forest and farm land areas. A recurrent pattern in the six communities was the presence of similar species in the forest and forest edge niches. This is due to the transitional character of the forest edge niche. Morphospecies 16 of the Reduviidae family was found most often in the forest and forest edge niches of the Altuspata and Choro Alto communities. It was absent in the Choro community. The area of study has insect species of the Pentatomidae and Reduviidae families that play important ecological roles - in some cases they can be pests and in others they can be predators of pests. There is a notable difference in the presence of insects from the Reduviidae and Pentatomidae families between municipalities. This difference is explained by the increased application of agrochemicals in the municipality of Coripata.

Cholinesterase (ChE) was histochemically localized by three methods in the sixth abdominal ganglion and the femur of crickets and cockroaches using light and electron microscopy. The light microscopy showed that ChE in insect femur could be readily demonstrated. The ultrastructural data showed enzyme activity: in ganglion - neural lamella, perineurium, axolemma, inside axons, along glia and at probable synapses; in peripheral nerves - in glial cells, sarcoplasmic reticulum, T-system, axolemma, sarcolemma and at neuromuscular junctions. All activity was inhibited with 10-4 eserine except in the neural lamella, suggesting cholinesterase at all of the above sites except the neural lamella where a non-specific esterase is present. This is the first histochemical localization of a cholinesterase in insect myoneural junctions. Barrnett, Karnovsky and Gomori methods were compared. Tissues were well penetrated with the Barrnett method. The Karnovsky technique provides poor ultrastructure. The Gomori method gives the best over-all results, although the end-product is rather diffuse.

LD2668 .T4 1962 K66

Difficulties in pollen transfer have adversely affected seed production of hybrid onion (Allium cepa L.) in the United States. Six onion cultivars were examined for differential attractiveness to the honey bee (Apis mellifera L.). Honey bees clearly discriminated between the onion cultivars in both open plots and caged plots. Nectar secretion, nectar sugar concentration, nectar sugar composition, mectar potassium content, and flower phenology were correlated with honey bee visitation. Nectar secretion rates ranged from 0.54 to 0.84 ul per floret per day. Onion cultivars also demonstrated differential flowering potential. The cultivars produced from 176 to 359 flowers per umbel with 32 to 74 umbels per 30 onions. All onion cultivars examinaed contained viscous nectar with sugar concentrations ranging from 51 to 65% of total dissolved solids. Onion nectar was analyzed by gas chromatography to determine qualitative sugar differences among onion cultivars. All cultivars were hexose dominant with an approximately 1:1 fructose:glucose ratio. However, fructose was slightly more abundant than glucose. Sucrose was much less abundant than the hexose sugars. Atomic absorption spectrophotometry revealed little difference in potassium content among the A. cepa cultivars. Nectar potassium levels ranged from 5,300 ppm to 6,900 ppm. Cultivars with higher nectar potassium levels had fewer honey bee visits. Two honey bee bioassays were conducted. The first bioassay simulated the sugar and potassium composition of each onion cultivar. The honey bees selectively foraged on simulated nectars with low potassium and high sugar concentrations. The second bioassay was designed to test honey bee response to "phenolic-rich" solutions. The natural compounds tested were dilutions of salt cedar (Tamarix pentandra Pall.) honey, almond (Prunus dulcis Mill.) honey, and aloe (Aloe littoralis L.) nectar. The pure synthetic compounds tested were caffeic acid and genestic acid. Generally, honey bees foraged preferentially on the lower phenolic concentrations, indicating that compounds high in phenolic composition inhibit honey bee foraging. Finally, seed yields of each of the cultivars were compared. Wide variations in yields were correlated with honey bee visitation, sugar composition, potassium levels, and flower phenology.

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