Ecology and Zoology

Bean (Phaseolus vulgaris) is the most important food legume, however there is an increasing decline in performance and production due to pest attack especially from the aphids. Pest infestation is even higher during the dry season hence causing a serious damage to the crop. Therefore there is an urgent need to come up with methods like integrated pest management in order to control the pest, which destroys the crop by sucking the nutrients, excrete honey dew which attract saprophytic fungi and is also known to transmit a number of viruses to the bean plant. The aim of this study was to: determine efficacy of integrated management on bean aphid infestation and to determine the efficacy of integrated management on bean performance. This was done with an overall aim of increasing the yields of beans. Data collection was done using a 4x2x2 factorial experiment comprising of Bean variety cv. Nyayo ,two rates of seed dressing chemical (with and without) using (Gaucho) Imidacloprid, two rates of botanical pesticide (Tephrosia vogelii) extract at 0 and 20w/v %) applied as a foliar spray and four rates of inorganic fertilizer Triple Super Phosphate (TSP)-zero rate (no fertilizer), Low rate (TSP at, 50 kg product/ha), medium rate, 75 kg/ha and high 100 kg product/ha). The four factors were combined in a completely factorial arrangement in randomized complete block design replicated three times constituting 16 treatment combination giving 48 experimental plots which were planted in five row field plots measuring 2m by 2.25 m. The experimental design was Randomized Complete Block Design (RCBD) replicated three times. Each experimental plot measured 2.0 M x 2.0 M with inter row and intra row spacing of 45 cm and 20 cm respectively. Clean bean variety seed sourced from local market was used in this study to reflect local farmer's source of planting material. Data collected on all the parameters was subjected to analysis of variance procedure using general linear model of the statistical analysis system (SAS) package (SAS Institute, 1996). However, data on aphid count and number of plants infested by bean aphids were first subjected to a transformation of square root of x+ 1 in order to reduce heterogeneity of the data before being analalysed. Mean separation was done according to Fisher's protected LSD significant difference Test at 5% level of significance. The Pearson's correlation test was performed on the means of the parameters investigated to compare on their relationships. Results showed that the aphid population builds up and damage in bean crop was significantly reduced when combined application of treatments of seed treatment using Imidacloprid at 700 ml/100kg seed was done on bean seed before planting and planting with 100 kg/ha of tsp fertilizer, then followed with a Biopesticide foliar spray of T. vogelii at 20%w/v from 30 days after emergence (30DAE) thereafter spraying on a weekly basis better than any other treatment applied. The application of T.vogelii at 20%w/v alone on weekly basis significantly reduced bean aphid infestation better than control and application of seed dress alone. Use of seed dressing alone was only temporary measure during seedling stages and should be supported with other control measure one month after crop emergence as it does not provide complete control of bean aphid infestation for the whole season during bean growth. The integration of TSP fertilizer, seed dresser, and application of foliar spray of Tephrosia leaf extract at 20%w/v greatly reduced Aphis fabae infestation and population build in bean crop below damaging levels and resulted in improved bean grain yield, Application of TSP fertilizer rates alone did not seem to have effect on bean aphid infestation on bean crop as population build up was observed under all the rates applied. It's therefore recommended to use integrated control in order to increase performance and production of beans.

Herbivory is a fundamental process that controls primary producer abundance and regulates energy and nutrient flows to higher trophic levels. Despite the recent proliferation of small-scale studies on herbivore effects on aquatic plants, there remains limited understanding of the factors that control consumer regulation of vascular plants in aquatic ecosystems. Our current knowledge of the regulation of primary producers has hindered efforts to understand the structure and functioning of aquatic ecosystems, and to manage such ecosystems effectively. We conducted a global meta-analysis of the outcomes of plant–herbivore interactions using a data set comprised of 326 values from 163 studies, in order to test two mechanistic hypotheses: first, that greater negative changes in plant abundance would be associated with higher herbivore biomass densities; second, that the magnitude of changes in plant abundance would vary with herbivore taxonomic identity. We found evidence that plant abundance declined with increased herbivore density, with plants eliminated at high densities. Significant between-taxa differences in impact were detected, with insects associated with smaller reductions in plant abundance than all other taxa. Similarly, birds caused smaller reductions in plant abundance than echinoderms, fish, or molluscs. Furthermore, larger reductions in plant abundance were detected for fish relative to crustaceans. We found a positive relationship between herbivore species richness and change in plant abundance, with the strongest reductions in plant abundance reported for low herbivore species richness, suggesting that greater herbivore diversity may protect against large reductions in plant abundance. Finally, we found that herbivore–plant nativeness was a key factor affecting the magnitude of herbivore impacts on plant abundance across a wide range of species assemblages. Assemblages comprised of invasive herbivores and native plant assemblages were associated with greater reductions in plant abundance compared with invasive herbivores and invasive plants, native herbivores and invasive plants, native herbivores and mixed-nativeness plants, and native herbivores and native plants. By contrast, assemblages comprised of native herbivores and invasive plants were associated with lower reductions in plant abundance compared with both mixed-nativeness herbivores and native plants, and native herbivores and native plants. However, the effects of herbivore–plant nativeness on changes in plant abundance were reduced at high herbivore densities. Our mean reductions in aquatic plant abundance are greater than those reported in the literature for terrestrial plants, but lower than aquatic algae. Our findings highlight the need for a substantial shift in how biologists incorporate plant–herbivore interactions into theories of aquatic ecosystem structure and functioning. Currently, the failure to incorporate top-down effects continues to hinder our capacity to understand and manage the ecological dynamics of habitats that contain aquatic plants.

In order that survival of young be more than optimum, the
timing of spawning by the mature adult fish is so adjusted that
must be closely linked to the availability of maximum congenial
environment added by increased food availability of food for the
newly hatched young ones. The availability of food for the larvae
and juveniles of most temperate and cold water fish species varies
on a seasonal basis and following this fish are usually found to have
a discrete and selective spawning season so perfectly timed that
hatched out larvae will get readily available exogenous food from
nature for their further development. Thus, in many temperate
and cold water species, spawning is an annual event. Spawning
culminates a series of preparatory events during which the
gametes develop and the gonads increase in size.

Food insecurity is a major problem facing the Kenyan populace. There are acute food shortages that do not satisfy the increasing population as traditional food stocks continue to be depleted as a result of environmental changes and increasing population. Faced with problems of food insecurity, increasing food prices and over-reliance on the traditional food items, there is an urgent need for Kenyans to diversify their food sources. In western Kenya, the termites have a long history of consumption as a delicacy during the rainy seasons. A major problem is that they are varied in species and may not all contain the ingredients required by humans for nutrition. There are also very few studies that have attempted to evaluate the totality of white ants in Kenya. The aim of this study was to determine the proximate composition of the termites in Western Kenya. This was done with an overall aim of determining whether termites can be declared as an alternative food source in Kenya. Data were collected and analyzed for proximate composition of moisture, protein, lipids, crude fiber. Essential Amino Acid (EAA) profiles were evaluated to determine protein composition. Food value of the different species was analyzed by Analysis of Variance (ANOVA). Results indicated that termites have high levels of moisture content of 90.2% crude protein (64%), crude lipids (9.35%), crude fibre (9.53), gross energy of 4.99 kcal and the essential amino acids at 31.5g/100g. Due to the conditions of families in Kenya this can be a substitute for the sources of protein substitute for red meat and Tilapia fish meals preferred by many households. The profile of Essential Amino Acid in the current study was found to be high and therefore white ants formed a very good source of essential amino acid to the local people. This study therefore concludes that white ants are suitable alternative food source to replace major rotein food and nutritionists should start a campaign of making the white ants a delicacy. Given that white ants are neglected food in Kenya, it is recommended that the food items should be consumed as one of the food in the traditional diets in areas where the species occur.

The termite alates of Pseudocanthotermes grandiceps are eaten as a substitute dietary element in Kenya. Artificial inducement of the alates was evaluated based on a traditional method that has been used for decades. The idea is to imitate the natural weather conditions required by swarming alates. In natural situations, the most conducive weather is when rain is accompanied by thunderstorms and then stops for at least 2days with intervals of clear and sunny skies. Such weather conditions stimulate the emergence of alates during day time. In artificial situation, producing the sound of rain to strengthen the impression of rain was found to work with Pseudocanthotermes species. Through field manipulation of weather conditions, the alates of P. grandiceps responded to external changes and were harvested for consumption by local community. The following weather conditions were found necessary in stimulating nest activities and emergence of alates: a) hot and dry weather for a week prior to artificial inducement; b) sunny and hot afternoon at time of swarming. The time taken from the onset of the experiment to the end of swarming was approximately 8 hours. The artificial inducement of alates was found to be effective, seasonal and limited only to the genus Pseudocanthotermes.

Bean (Phaseolus vulgaris) is the most important food legume, however there is an increasing decline in performance and production due to pest attack especially from the aphids. Pest infestation is even higher during the dry season hence causing a serious damage to the crop. Therefore there is an urgent need to come up with methods like integrated pest management in order to control the pest, which destroys the crop by sucking the nutrients, excrete honey dew which attract saprophytic fungi and is also known to transmit a number of viruses to the bean plant. The aim of this study was to: determine efficacy of integrated management on bean aphid infestation and to determine the efficacy of integrated management on bean performance. This was done with an overall aim of increasing the yields of beans. Data collection was done using a 4x2x2 factorial experiment comprising of Bean variety cv. Nyayo ,two rates of seed dressing chemical (with and without) using (Gaucho) Imidacloprid, two ra...

Bean (Phaseolus vulgaris) is the most important food legume, however there is an increasing decline in performance and production due to pest attack especially from the aphids. Pest infestation is even higher during the dry season hence causing a serious damage to the crop. Therefore there is an urgent need to come up with methods like integrated pest management in order to control the pest, which destroys the crop by sucking the nutrients, excrete honey dew which attract saprophytic fungi and is also known to transmit a number of viruses to the bean plant. The aim of this study was to: determine efficacy of integrated management on bean aphid infestation and to determine the efficacy of integrated management on bean performance. This was done with an overall aim of increasing the yields of beans. Data collection was done using a 4x2x2 factorial experiment comprising of Bean variety cv. Nyayo ,two rates of seed dressing chemical (with and without) using (Gaucho) Imidacloprid, two ra...