Glossina fuscipes

When the male G. fuscipes is examined from the ventral side, a rounded structure named the hypopygium can be seen at the posterior end of the abdomen. Immediately in front of the hypopygium is a plate bearing dark hairs called hectors. Both the hypopygium and the hectors help distinguish male from females and serve to grasp onto the end of the female abdomen during mating. As copulation commences, the hypopygium unfolds to uncover superior and inferior claspers as well as the aedeagus.[4]

The end of the female abdomen lacks any significant structures that would be the counterpart of the male hypopygium and hectors; however, females display a vulva, which can exhibit several small plates that aid in species identification.[4]

In a few hours, the sperm move from the spermatophore into the spermatheca, where they remain active for the remainder of the female's life. Eggs are fertilized immediately as they enter the uterus by sperm from the spermatheca that come into contact and penetrate the anterior portion of the egg. The fertilized egg remains in the uterus for about four days as the instar larva begins to develop.[4]

Once she has mated, a female can produce larvae for the remainder of her life. At about 25 °C, a female fly will produce mature larva every 9–10 days with the exception of the first, which may take up to 18–20 days. Lower temperatures result in a lower rate of breeding whereas higher temperatures increase the rate of breeding. Temperatures either too high or too low may cease breeding altogether.[5]

The G. fuscipes larva in passes through three instars as it grows up to when the fully grown larva is dropped by a female fly. The larva has a mouth at the anterior end and two spiracles at the posterior end. Rather unusually, the larva spends most of its time and does all its feeding within the mother's body.

Apart from food stored in the egg, the food supply for the three larval instar stages comes from the mother's milk gland. The milky secretions of this gland are expelled out of the gland duct at the head end of the larva. The larva sucks up the milky secretion and passes it directly to the midgut where it is slowly digested and assimilated.

For air supply, the larva depends on air entering the vulva of the female. The air must pass into the female's posterior spiracles or polypneustic lobes to reach the larva.[4]

If a larva fails to reach its full size, it will be prematurely expelled from the uterus. The aborted larva dies. Abortions could be due to the mother fly not obtaining enough food or also when carelessly handled or exposed to insecticide. Eggs are subjected to abortion for the same reasons.[4]

The pupa is a dark brown, shorter than the larva that produced it, and rounded with polypneustic lobes at the posterior end. The lobes are distinctively shaped and can help to distinguish the G. fuscipes pupa from that of other flies. The pupa also has a hard case on its outside called the puparium.

The pupal stage lasts about four to five weeks according to temperature. Higher temperatures shorten the pupal period. In contrast, lower temperatures lengthen the pupal period to more than 50 days in certain climates. However, temperature extremes will cause death.[4]

When ready to emerge, the young adult fly expands its ptilinum to burst open puparium's end. Out of the fresh hole and surrounding soil, the adult emerges by using the ptilinum, struggling to the top of the soil and into open air. At this stage, the adult's body is very soft while its wings are small and crumpled. After a few urinations, the wings will expand towards their proper size. From the time between the emergence of the fly and its first meal, the adult is called a teneral fly. After the first blood meal has been taken, the fly is then termed a non-teneral fly.[4]

During mating, males settle on the back of the female. Claspers at the posterior end of the male abdomen unfold in order to grip the end of the female abdomen. This mating position may be maintained for an hour or two before the duo parts.

Females typically mate a young age, either before or around the same time of their first blood meals. Females usually mate only once in their lives though it is possible mate more than once, whereas males tend to mate several times. Older males are more likely to mate successfully than very young males.

During mating, the aedeagus is inserted into the vulva and reaches into the uterus as far as the spermatheca exit. A sizable ball of sperm is deposited there in the form of a spermatophore. At the conclusion of mating, the male releases his grip on the female before flying away.[4]

G. fuscipes, alongside other tsetse flies, are prominent biological vectors of protozoan parasites belonging to the genus Trypanosoma known to cause the namesake diseases in various vertebrate species including humans, antelopes, bovine cattle, camels, horses, sheep, goats, and pigs. The parasites are transmitted to humans via bites from G. fuscipes, which have acquired their infection from other human beings or animals harboring human-pathogenic parasites.[8]

The table below summarizes this information for the G. fuscipes species; however, the diseases listed below may be transferred by other tsetse fly species in addition to G. fuscipes.

The containment of sleeping sickness and nagana would be of great benefit to rural communities in sub-Saharan Africa, alleviating poverty and improving food security, thus efforts are undertaken in rein in local populations of G. fuscipes via methods such as pesticide campaigns, trapping, or the sterile insect technique.[9]

G. fuscipes flies rely on the obligate symbiont bacterial genus Wigglesworthia to supplement their diets with nutrients essential for fecundity.[10] The adult immune system relies similarly on Wigglesworthia for activation and development.[11] A secondary, facultative symbiont is the genus Sodalis, which is present in tsetse populations considered to play a role in the ability to transmit trypanosomes.[12] Finally, the third symbiont is the genus Wolbachia, transovarially transmitted between generations. To enhance transmission and survival, Wolbachia has evolved mechanisms to alter host reproduction.[13]

Using both culture-dependent and independent methods, it was shown that Kenyan populations of subspecies G. f. fuscipes harbor diverse range of bacteria. Of the flies tested, bacteria were isolated from 72% of the sample population with 23 bacterial species identified. Of these, the Firmicutes phylum constituted 16 species, seven of which belong to the genus Bacillus.[14]