Genus Thestor: 2 species and their Characters

T. protumnus:
Nominate found in Cape Peninsula
Eggs laid near Ants nests, often singularly but some in clusters
Larvae hatches and by 3rd instar, taken by Ants into underground chambers where it is possibly fed by them, and feeds further on live Coccids (Homoptera), enticing them closer and to remain calm with pheromones. Total length at end of 3rd instar is +-6mm
Once larvae is midway into 4th instar, it will enter into pupation and if need be remain in diapause in this state (up to 30 days) until conditions are favourable before chrysalis emerges, or else it will enter a new larval instar. By end of 4th instar, larva is 18mm long
Pupation is on hollow of ants nest just beneath soil or rock

T. basutus spp. basutus:
Found in higher lying areas from Eastern Cape, through Natal and Mpumalanga Drakensberg escarpment and slightly further north
Eggs laid mostly singularly, broader gaps between oviposition
Larvae hatches and feeds on Verbena plants also visited by Ants and Homoptera, but only at the end of 4th instar is it taken by ants into the nest and left unattended to pupate soon after. At end of 3rd instar, measures 7mm in length, and reaches 18mm in an indeterminate amount of time (perhaps responding to environmental cues)
An additional brood may occur in some populations (perhaps as a factor of geographic position)
Pupa formed in Ants nest, where Chrysalis emerges and slowly exits the tunnels

Conclusion:
T. protumnus adapted to edaphic specialization through contigency with highly localized weather events in a smaller geographic space (larvae grow slower than T. basutus but can stay underground longer?) in addition to possible higher flexibility in oviposition spatial selection (switching from singular to clustering). Evidenced in in fresh Chrysalis sightings from September through to early January

T. basutus ssp. basutus adapted to broader scale climatic onsets which are less predictable (front blowing in snow or cold weather to the mountains). Grows faster, possibly pupates faster (?), maybe in response to the requirement of more time 'on-the'wing' to find colonies of larval foodplants segmented in the grassland landscape. Can't spend too long in ants nest but can do 2 broods, if perhaps one should fail to produce a certain threshold of adult recruitment

Source: Life Histories of the South African Lycaenid Butterflies; by G.C Clark and C.G Dickson (Purnell; 1971)

Posted on July 1, 2022 12:02 PM by