Interpreting morphological adaptations associated with viviparity in the Tsetse fly Glossina morsitans (Westwood) by three-dimensional analysis

September 23, 2020

Geoffrey M Attardo (1), Nicole Tam (1), Dula Parkinson (2), Lindsey K Mack (1), Xavier J Zahnle (1), Joceline Arguellez (1), Peter Takác (3,4), Anna R Malacrida (5)
Insects, 11, September 2020: 651. DOI: 10.3390/insects11100651


MicroCT, Glossina, tsetse, reproduction, morphology, computed tomography, viviparity, trypanosomiasis


Tsetse flies (genus Glossina), the sole vectors of African trypanosomiasis, are distinct from most other insects, due to dramatic morphological and physiological adaptations required to support their unique biology. These adaptations are driven by demands associated with obligate hematophagy and viviparous reproduction. Obligate viviparity entails intrauterine larval development and the provision of maternal nutrients for the developing larvae. The reduced reproductive capacity/rate associated with this biology results in increased inter- and intra-sexual competition. Here, we use phase contrast microcomputed tomography (pcMicroCT) to analyze morphological adaptations associated with viviparous biology. These include (1) modifications facilitating abdominal distention required during blood feeding and pregnancy, (2) abdominal and uterine musculature adaptations for gestation and parturition of developed larvae, (3) reduced ovarian structure and capacity, (4) structural features of the male-derived spermatophore optimizing semen/sperm delivery and inhibition of insemination by competing males and (5) structural features of the milk gland facilitating nutrient incorporation and transfer into the uterus. Three-dimensional analysis of these features provides unprecedented opportunities for examination and discovery of internal morphological features not possible with traditional microscopy techniques and provides new opportunities for comparative morphological analyses over time and between species.

How Our Software Was Used

Dragonfly was used for data analysis and visualization. It was also used to calculate tissue volumes, surface areas and thickness mapping (by measuring segmented voxels) and to generate the associated video.

Author Affiliation

(1) Department of Entomology and Nematology, University of California, Davis, CA 95616, USA.
(2) Lawrence Berkeley National Lab., Berkeley, CA 94720, USA.
(3) Department of Animal Systematics, Institute of Zoology, Slovak Academy of Sciences, 84506 Bratislava, Slovakia.
(4) Scientica, Ltd., 831 06 Bratislava, Slovakia.
(5) Department of Biology and Biotechnology, University of Pavia, 27100 Pavia, Italy.