The impact of geographical origin of two strains of the herbivore, Eccritotarsus catarinensis, on several fitness traits in response to temperature

Cryptic species of a water hyacinth biological control agent revealed in South Africa: host specificity, impact, and thermal tolerance

“…The Pontederiaceae in southern Africa are also taxonomically isolated with the closest relatives being the Commelinaceae, which are not morphologically similar and are not aquatic. Eccritotarsus eichhorniae was shown to be more tolerant of constant 30°C, in terms of egg hatching rate and survival of nymphs, than E. catarinensis, which could not complete multiple generations at this relatively high temperature (Ismail & Brooks, 2016). The host specificity results for E. eichhorniae presented here are supported by field observations in Peru where this insect was only recorded on E. crassipes despite a diversity of Pontederiaceae growing sympatrically (Cordo, 1999).…”

“…Only test plant species within the Pontederiaceae were tested for E. eichhorniae because its host range within the plant family was even more restricted than that of E. catarinensis. Paterson et al (2016) found no significant difference in fecundity of the two species, but fecundity differs with temperature and E. eichhorniae has a higher fecundity at higher temperatures (Ismail & Brooks, 2016). Testing of plant species outside of the Pontederiaceae was therefore not required for E. eichhorniae because a large phylogenetic gap in the host range is extremely unlikely and no plants within southern Africa are closely related enough to be at risk besides those that were tested in this study.…”

Thermal plasticity and microevolution enhance establishment success and persistence of a water hyacinth biological control agent

“…The thermal physiology of E. catarinensis makes the species more tolerant of cold and less tolerant of heat than the very similar cryptic species, E. eichhorniae, which is indigenous to a much warmer region in Peru (Ismail & Brookes, 2016). The thermal physiology of E. catarinensis makes the species more tolerant of cold and less tolerant of heat than the very similar cryptic species, E. eichhorniae, which is indigenous to a much warmer region in Peru (Ismail & Brookes, 2016).…”

“…The South African population of E. catarinensis is known to have undergone a severe genetic bottleneck in quarantine that has resulted in reduced genetic diversity and, although some recovery in genetic diversity has been recorded since establishment, E. catarinensis in South Africa still has a much lower level of genetic diversity than a very similar and closely related cryptic species, Eccritotarsus eichhorniae Henry (Taylor et al, 2011;Paterson et al, 2016Paterson et al, ,2019. Eccritotarsus eichhorniae is indigenous to Peru where temperatures are much higher than in the native range of E. catarinensis in southern Brazil, so E. eichhorniae is expected to be less tolerant of cold conditions (Paterson et al, 2016(Paterson et al, , 2019Ismail & Brookes, 2016). Eccritotarsus eichhorniae is indigenous to Peru where temperatures are much higher than in the native range of E. catarinensis in southern Brazil, so E. eichhorniae is expected to be less tolerant of cold conditions (Paterson et al, 2016(Paterson et al, , 2019Ismail & Brookes, 2016).…”

“…This latter species was also introduced into South Africa as a biocontrol agent, but was never subjected to as severe a genetic bottleneck (Taylor et al, 2011;Paterson et al, 2016Paterson et al, ,2019. Eccritotarsus eichhorniae is indigenous to Peru where temperatures are much higher than in the native range of E. catarinensis in southern Brazil, so E. eichhorniae is expected to be less tolerant of cold conditions (Paterson et al, 2016(Paterson et al, , 2019Ismail & Brookes, 2016). The much higher levels of genetic diversity in E. eichhorniae (Taylor et al, 2011) may, on the other hand, make this species more amenable to evolutionary change, resulting in a better adapted biocontrol agent in future.…”