Browsing by Author "Mohamed, Samira A."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Annual Diversity of Honey Bee pollen Sources in Two Pumpkin Growing Landscapes, Machakos County, Kenya
    (Journal of Pollination Ecology, 2025-03) Nang’oni, Marystella W.; Kasina, Muo; Karanja, Rebecca; Guantai, Mary M.; Kinyanjui, Rahab N.; Omuse, Evanson R.; Lattorf, H. Michael G.; Abdel-Rahman, Elfatih M.; Adan, Marian; Mohamed, Samira A.; Dubois, Thomas
    Multi-floral foraging sources for honey bee (Apis mellifera L.) have been threatened by landscape changes and unsustainable farming practices. In East Africa, the biodiversity of forage resources that could support honey bees, especially in agricultural lands, remains least explored. This study investigated pollen diversity for honey bees in Yatta and Masinga Sub-counties in Machakos County, Kenya. Honey bee hives were installed on eight pumpkin (Cucurbita maxima Duchesne ex Lam) farms (one hive per farm) in two varying landscape vegetation classes (low and medium) based on normalized difference vegetation index (NDVI). Pollen traps were installed at the hive entrance and pollen pellets were retrieved fortnightly for subsequent identification. Approximately 115 pollen types were identified. The pollen pellets were associated with 63 plant families and 109 plant families in low and medium NDVI classes, respectively. The predominant source of pollen for honey bees in low NDVI class included the plant families Poaceae (5,526 pellets), Asteraceae (3,176 pellets), Combretaceae (1,327 pellets), Acanthaceae (1,122 pellets), Amaranthaceae (960 pellets), Boraginaceae (951 pellets), Typhaceae (889 pellets), Guaduelleae (809 pellets) and Loranthaceae (588 pellets). In medium NDVI, most pollen was sourced from plant family Asteraceae (3,605 pellets), Malvaceae (1,572 pellets), Poaceae (1,538 pellets), Combretaceae (1,468 pellets), Salvadoraceae (1,354 pellets), Solanaceae (1,011 pellets), Asphodelaceae (885 pellets), Fabaceae (882 pellets), Euphorbiaceae (685 pellets) and Myrtaceae (546 pellets). The diversity of pollen types varied between the NDVI classes and across months. Although honey bees sourced diverse pollen required for the dietary balance of the colony, there was variability across landscape types and months.
  • Thumbnail Image
    Item
    Differential Responses of the Egg-Larval Parasitoid Chelonus Bifoveolatus To Fall Armyworm-Induced and Constitutive Volatiles of Diverse Maize Genotypes
    (International Centre of Insect Physiology and Ecology, 2025-04-01) Onjura, Collins O.; Peter, Emmanuel; Asudi, George O.; Gicheru, Michael M.; Mohamed, Samira A.
    The fall armyworm (FAW), Spodoptera frugiperda, is a serious invasive crop pest and threat to food security. Conventional pest control approaches using chemical pesticides can lead to adverse environmental and human health problems calling for safer alternative pest management options. Volatile organic compounds (VOCs) released by plants constitutively and in response to herbivory have been shown to enhance ecologically benign biocontrol alternatives to chemical insecticides for pest management. However, genotypic variations in VOC emissions have also been reported for plant species including maize (Zea mays). Hence, a better insight into the variations in odor profiles of different maize varieties and their corresponding role in recruiting pests’ natural enemies are crucial for developing a sustainable biocontrol strategy. Our present study assessed the behavioral responses of the FAW egg-larval parasitoid, Chelonus bifoveolatus (Braconidae: Hymenoptera), to constitutive and induced volatiles from different maize landraces (Jowi Red, Nyamula) and hybrids (SC Duma, DK 777) grown in Kenya and compared their volatile profiles. In a four-arm olfactometer, female parasitoid wasps were significantly attracted to FAW oviposition-induced VOCs from SC Duma and Nyamula. Chemical analysis of test plant volatiles revealed significant variation in the quantity and quality of key bioactive VOCs such as (E)-2-hexenal, α-pinene, (Z)-3-hexenyl acetate, (E)-4,8-dimethyl-1,3,7-nonatriene, α-copaene, (E)-β-farnesene and (E, E)-4,8,12-trimethyl-1,3,7,11- tridecatetraene. Our findings provide more insights into genetic variation in VOCs emission across maize genotypes and the corresponding differences in attraction of pest natural enemies that provide indirect defense. As such, these traits could be exploited to enhance ecologically sustainable pest management strategies.