African queens find mates when males are rare

This is the final version. Available from Wiley via the DOI in this record. DATA AVAILABILITY STATEMENT: Sex ratio, spermatophore numbers and Rcode: Figshare doi:10.6084/ m9.figshare.21947729.In butterflies and moths, male-killing endosymbionts are transmitted from infected females via their eggs, and the male progeny then perish. This means that successful transmission of the parasite relies on the successful mating of the host. Paradoxically, at the population level, parasite transmission also reduces the number of adult males present in the final population for infected females to mate with. Here we investigate if successful female mating when males are rare is indeed a likely rate-limiting step in the transmission of male-killing Spiroplasma in the African Monarch, Danaus chrysippus. In Lepidoptera, successful pairings are hallmarked by the transfer of a sperm-containing spermatophore from the male to the female during copulation. Conveniently, this spermatophore remains detectable within the female upon dissection, and thus, spermatophore counts can be used to assess the frequency of successful mating in the field. We used such spermatophore counts to examine if altered sex ratios in the D. chrysippus do indeed affect female mating success. We examined two different field sites in East Africa where males were often rare. Surprisingly, mated females carried an average of 1.5 spermatophores each, regardless of male frequency, and importantly, only 10-20% remained unmated. This suggests that infected females will still be able to mate in the face of either Spiroplasma-mediated male killing and/or fluctuations in adult sex ratio over the wet-dry season cycle. These observations may begin to explain how the male-killing mollicute can still be successfully transmitted in a population where males are rare.National Geographic SocietyRoyal Societ

East Africa Future Water Scenarios to 2050

We have analysed two possible development scenarios for the extended Lake Victoria Basin (eLVB.) Each scenario combines a plausible socio-economic development pathway with climate change impacts calculated for the GHG concentration pathway RCP6.0 (i.e. medium climate change). A Reference Scenario (REF) applies the storyline and quantification of one of the IPCC’s Shared Socio-economic Pathways (SSP), the ‘Middle of the Road’ scenario (SSP2). The East-Africa Regional Vision scenario (EA-RVS) portrays the vision of the region, as expressed in several vision studies and the first stakeholder workshop of the study. - Data comes as Excel files - Supplementary to the report: East Africa Water Scenarios to 2050 - The Excel Files have been used in the second workshop “East Africa Future Water Scenarios to 2050”, from December 4-6, 2018 in Entebbe, Uganda, for consultation and joint learning and for discussion and fine-tuning of modelling result

Assessment of aflatoxin and fumonisin contamination levels in maize and mycotoxins awareness and risk factors in Rwanda

Mycotoxins are secondary metabolites of fungi that are toxic to humans and animals when consumed in contaminated food and feed. The Rwandan climate conditions like steady temperature and sufficient rainfall favor the growth of fungi leading to high probability of mycotoxins contamination. Mycotoxins get into maize throughout the value chain from the field to processed products. Maize is  promoted in Rwanda under the Crop Intensification Program (CIP), for nutrition and food security. The aim of the study was to evaluate mycotoxins (Aflatoxin and fumonisin) levels in maize and assess awareness and factors associated with mycotoxin contamination in Rwanda. Maize samples (227 kg) from season B 2019 were collected in 15 Districts in five provinces of Rwanda after an interview with a representative of the household or cooperative using a structured questionnaire. The samples were analyzed for aflatoxin and  fumonisin using Reveal Q+ and AccuScan Gold Reader. From the interview, most of the respondents were not aware about aflatoxin (59.7 %) and 99 % did not know the effect of mycotoxins on human health. The average of aflatoxin contamination in surveyed districts was 6.69±13 μg/kg. In general, 90.4 % of samples scored below the limit of aflatoxin level regulated in East Africa/Kenya regulation standards (10 μg/kg). The levels of aflatoxin ranged between 0 and 100.9 μg/kg. The means aflatoxin levels within districts ranged between 1.36±0.5 μg/kg and 13.75±25 μg/kg. Among 9.6 % of the samples containing aflatoxins above the EU and Kenyan regulations standard limit, 5.7 % were above the US standards of 20 μg/kg. Within clusters, the level of aflatoxin more than 10 μg/kg was 5 %, 7 % and 18 % for stores, household and market samples, respectively. From the study, as mechanical damage of grains, moisture content of grains and the temperature of the store house increased, Aflatoxin level also increased. Fumonisin analyzed in maize ranged from 0 to 2.3 μg/g and only one sample from market showed a slightly higher level of fumonisin than the EU and US limit of 2 μg/g. More effort for aflatoxin mitigation is needed at the market level. Farmers need to be aware and taught how they can improve their agricultural system and more knowledge on mycotoxin control is needed. The results point to appropriate measures to recommend for control ofmycotoxins in Rwanda and awareness creation. Key words: AccuScan, Aflatoxin, Fumonisin, Fungal, Maize, Mycotoxins, Reveal Q+, Rwand

Slaughter weight rather than sex affects carcass cuts and tissue composition of Bisaro pigs

Carcass cuts and tissue composition were assessed in Bisaro pigs (n=64) from two sexes (31 gilts and 33 entire males) reared until three target slaughter body-weights (BW) means: 17 kg, 32 kg, and 79 kg. Dressing percentage and backfat thickness increased whereas carcass shrinkage decreased with increasing BW. Slaughter weight affected most of the carcass cut proportions, except shoulder and thoracic regions. Bone proportion decreased linearly with increasing slaughter BW, while intermuscular and subcutaneous adipose tissue depots increased concomitantly. Slaughter weight increased the subcutaneous adipose tissue proportion but this impaired intramuscular and intermuscular adipose tissues in the loin primal. The sex of the pigs minimally affected the carcass composition, as only the belly weight and the subcutaneous adipose tissue proportions were greater in gilts than in entire males. Light pigs regardless of sex are recommended to balance the trade-offs between carcass cuts and their non-edible compositional outcomes.Work included in the Portuguese PRODER research Project BISOPORC – Pork extensive production of Bísara breed, in two alternative systems: fattening on concentrate vs chesnut, Project PRODER SI I&DT Medida 4.1 “Cooperação para a Inovação”. The authors are grateful to Laboratory of Carcass and Meat Quality of Agriculture School of Polytechnic Institute of Bragança ‘Cantinho do Alfredo’. The authors are members of the MARCARNE network, funded by CYTED (ref. 116RT0503).info:eu-repo/semantics/publishedVersio

Effect of spacing on performance of teak at Longuza, Tanga, Tanzania

Forest Research Institute Malaysia is collaborating with JSTOR to digitize, preserve and extend access to Journal of Tropical Forest ScienceThe performance of teak ( Tectona grandis ) planted at four square spacings ( 1 .5, 2.0, 2.5 and 3.0 m) at Longuza, Tanga, in Tanzania was assessed. The variables studied were diameter at breast height (dbh) , total height and height to the first live branch, survival, number of branches, basal area and volume production at ages 1, 3, 7 and 9 y, and basic density and some strength properties at the age of 1 4 y. Results showed that dbh, number of branches, total height, basal area, basic density and some strength properties were significantly affected by spacing (p = 0.05). The diameter at breast height and number of branches increased with increasing spacing, while basal area decreased. All other variables were not significantly affected by spacing. A spacing of 3.0 m resulted in large diameter trees and later thinnings, with less total volume per hectare. The current spacing of 2 m resulted in higher volume per hectare of small sized trees which could be improved by thinning. It is recommended to continue with this spacing and the current thinning schedule until information on the economic implications of alternative regimes is available

Effect of spacing on performance of teak at Longuza, Tanga, Tanzania

Forest Research Institute Malaysia is collaborating with JSTOR to digitize, preserve and extend access to Journal of Tropical Forest ScienceThe performance of teak ( Tectona grandis ) planted at four square spacings ( 1 .5, 2.0, 2.5 and 3.0 m) at Longuza, Tanga, in Tanzania was assessed. The variables studied were diameter at breast height (dbh) , total height and height to the first live branch, survival, number of branches, basal area and volume production at ages 1, 3, 7 and 9 y, and basic density and some strength properties at the age of 1 4 y. Results showed that dbh, number of branches, total height, basal area, basic density and some strength properties were significantly affected by spacing (p = 0.05). The diameter at breast height and number of branches increased with increasing spacing, while basal area decreased. All other variables were not significantly affected by spacing. A spacing of 3.0 m resulted in large diameter trees and later thinnings, with less total volume per hectare. The current spacing of 2 m resulted in higher volume per hectare of small sized trees which could be improved by thinning. It is recommended to continue with this spacing and the current thinning schedule until information on the economic implications of alternative regimes is available

Identification des plantes menacées du Burundi par l’analyse de la vulnérabilité.

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