Flower visiting flies (insecta: diptera) communities in cucurbit production systems in Morogoro region, eastern central Tanzania
Loading...
Date
2021
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Sokoine University of Agriculture
Abstract
Flower visiting flies are one of the most important beneficial groups of Diptera because of
their profound pollination services to more than 19% of flowering plants. Many beneficial
insects such as bees which pollinate more than 51% of the flowering plants are serious
declining in the ecosystems. The production of many insect-dependent crops are at high
risk.
Previous studies indicated that some families of flower visiting flies contain
efficient pollinator species (Larson et al., 2001). These species could be of great
importance in maintaining ecosystem service and safeguarding the production of many
flowering plants including cucurbit crops. However, knowledge on community structures
and visitation rates of flower visiting flies associated with cultivated cucurbit crops is
limited in Tanzania. A thoroughly understanding of community structures and visitation
rates of flower visiting flies is a prerequisite if their potential is to be realized in
agriculture. Therefore, this study assessed the community structures and flower visit
activities of flower visiting flies associated with cucurbitaceous production systems in the
Morogoro region.
Experiments were laid out in a full factorial design. Factors were seasons, agroecological
zones, flowering weeks and fly species. Sampling of flies visiting cucurbit flowers was
carried out using yellow pan traps and a hand net supplemented with observational
counts, in ten established cucurbit fields across the mountainous and plateau zone of the
Morogoro region from March to July 2020.
A total of 7 606 specimens belonged to 22 genera and 8 families of flower vising flies
were collected during the study period. Of which 77.58% of all specimens were collected
from mountainous zone and the remaining 22.42% were from the plateau zone. Among
the hoverfly species examined, Eristalinus megacephalus Rossi, Mesembrius caffer Loewiii
and Toxomerus floralis Macquart showed significant variation in visitation rate, foraging
time and abundance across the two agroecological zones, season and sampling weeks
(P<0.05). The abundance of these species fluctuated significantly across the two
agroecological zones between the wet and dry season (P<0.05). On other hand, both
Shannon, Simpson and Margalef indexes placed the mountainous zone as the most
abundant and species rich zone in term of number of species. Species abundance
distribution models indicated hierarchically arrangement of flower visiting fly’s
communities within cucurbit crops.
All fields were highly similar as most of
the species were shared between fields within each zone.
Agroecosystems at different altitudes have different community structures and species
within these ecosystems differ in floral visitation rates. The obtained data so far seem to
suggest that hoverfly species should be considered as an important pollinators of cucurbit
crops. We recommend that a detailed study of pollination efficiency, floral preference and
diurnal activities of hoverfly species should therefore be considered a high priority.
Description
Dissertation
Keywords
Flower visiting flies, Diversity,curbit crops, Visitation rate., Hover fly,