Performance analysis of a basin-type solar still during harmattan

This study investigates the variational effect of climate factors on the productivity of a basin-type solar still during the harmattan season under the tropical savanna climate. The study was extended to examine the influences of selected climatic, operational, and design (COD) parameters on productivity. Additionally, the efficiency of solar still in removing water impurities during harmattan was also investigated. Explorative data and statistical analysis, and laboratory testing methods were used for these investigations. Results show that seasonal effects of harmattan can either increase or lower productivity. The effect of wind speed on productivity was not clearly defined during the harmattan season. Although high irradiation is essential for increased productivity, its effect is modified by other factors. Water temperature is the most significant to productivity amongst selected factors studied via the design of experiment (DOE). Moreover, the effect of harmattan on the water quality produced was not established. The main contribution of this work is the insights generated for both qualitative and quantitative reliability performance of a basin-type solar still under prevailing climate conditions.

Selection Gain of Maize Haploid Inducers for the Tropical Savanna Environments

Lacking elite haploid inducers performing high haploid induction rate (HIR) and agronomic performance is one of fundamental factors hindering the rapid adoption of doubled haploid technology in maize hybrid breeding, especially under tropical savanna climate. Breeding haploid inducers for specific agro-ecology, thus, is indispensable yet challenging. We used temperate inducer Stock6 as genetic source for haploid induction ability and eight tropical maize genotypes as principal donors for agronomic adaptation. Three cycles of modified ear-to-row with 5% intra-family selection were applied in a population set of 78 putative haploid inducer families emphasized on agronomic performance, R1-nj anthocyanin intensity, and inducer seed set. Genetic gains, variance components, and heritability on given traits were estimated. Hierarchical clustering based on five selection criteria was performed to investigate the phenotypic diversity of putative families. Cycle effect was predominant for all observed traits. Realized genetic gain was positive for HIR (0.40% per cycle) and inducer seed set (30.10% or 47.30 seeds per ear per cycle). In this study, we reported the first haploid inducers for regions under tropical savanna climate. Three inducer families, KHI-42, KHI-54, and KHI-64, were promising as they possessed HIR about 7.8% or 14 haploid seeds per tester ear and inducer seed rate about 95.0% or 208 inducer seeds per ear. The breeding method was effective for enhancing the seed set and the expression of R1-nj anthocyanin marker of inducers, yet it showed a low effectiveness to improve haploid induction rate. Introgression of temperate inducer Stock6 into tropical gene pool followed by phenotypic selections through modified ear-to-row selection on inducer seed set and R1-nj marker did not compromise the agronomic traits of tropical inducer families. Implications and further strategies for optimizing genetic gain on HIR are discussed.

Contributions to the knowledge of Neotropical Castianeirinae (Araneae: Corinnidae): redescription of Castianeira spinipalpis Mello-Leitão, 1945, with first description of the male, and description of a new Myrmecotypus O. Pickard-Cambridge, 1894 from the Bolivian Moxos plains

Two Neotropical species of the subfamily Castianeirinae are treated herein. Castianeira spinipalpis Mello-Leitão, 1945 was described from a single female specimen; we provide a redescription of the female and the male is described for the first time. The species is newly recorded from Paraguay and Bolivia. Also, Myrmecotypus rubioi sp. nov. is described from the Bolivian Moxos plains, a tropical savanna ecoregion of the Beni department of northern Bolivia. The new species can be distinguished from others in the genus by having tibia I spination 3-2, coxa II whitish (the remainder dark), and a unique male palpal embolus with two broad embolic discs basal to the embolus tip.

Multiple cues guarantee successful predation by a Neotropical wasp

Predatory social wasps are well studied in several aspects; however, foraging behaviour, especially that which takes place away from the nest at often unpredictable locations, or specialized behaviours to find and subdue prey are not well understood. In the Brazilian tropical savanna, the Polistinae wasp Brachygastra lecheguana is specialized in preying on some endophytic weevil larvae which develops inside floral buds. We hypothesized that these wasps utilize a combination of different mechanisms such as visual, chemical (odour) and possible tactile cues to find the weevil larvae. Using a combination of experimental manipulations (visual; chemical; visual/chemical) we tested the wasp’s ability to detect the endophytic larvae in the field. Additionally, we checked the ability of this wasp to detect vibrations produced by the weevils inside the buds. Our results suggest that the B. lecheguana wasp utilizes a sequence of eco-physiological mechanisms to find the endophytic larva inside floral buds: sight, smell, and perhaps touch. The use of multiple cues by this wasp guarantees such a high rate of predation on endophytic beetles that the wasp may have positive implications (reduction in weevils’ infestation) for the future of the host plant’s reproduction.