×

Warning

JUser: :_load: Unable to load user with ID: 504

Notice

Thank you for visiting our website.

Please note that the site is not fully functional at the moment as we are in the process of re-developing. We hope that you will find the available resources helpful in the meantime.

German wasp | Vespula germanica

German wasp

Vespula germanica

Coral bush | Ardisia crenata

Coral bush

Ardisia crenata

Purple loosestrife | Lythrum salicaria

Purple loosestrife

Lythrum salicaria

Pom pom weed | Campuloclinium macrocephalum

Pom pom weed

Campuloclinium macrocephalum

Canarybird bush | Crotalaria agatiflora

Canarybird bush

Crotalaria agatiflora

Peanut butter cassia | Senna didymobotrya

Peanut butter cassia

Senna didymobotrya

Rubber vine | Cryptostegia grandiflora

Rubber vine

Cryptostegia grandiflora

1 2 3 4 5 6 7

Environmental Programmes

In order to tackle our country’s socio-economic challenges, the government adopted the Outcomes based approach to improve government performance and providing focus on service delivery. find out more

Does phenotypic plasticity influence the thermal physiology of Eccritotarsus catarinensis?

Does phenotypic plasticity influence the thermal physiology of Eccritotarsus catarinensis?
Tamzin GRIFFITH1, Iain D. Paterson1, Julie A. Coetzee2
1Biological Control Research Group, Department of Zoology & Entomology, Rhodes University, Grahamstown, 6140 South Africa
2Department of Botany, Rhodes University, Grahamstown, 6140 South Africa 

Eccritotarsus catarinensis (Carvalho) (Miridae), a biological control agent for water hyacinth, Eichhornia crassipes (Mart.) Solms (Pontederiaceae) has failed to establish in some parts of South Africa due to climatic incompatibility. Some insects have the ability to change their thermal tolerance according to the temperatures they are exposed to, without a change in their genotype. This is known as phenotypic plasticity. Thermal tolerance of two populations of E. catarinensis from different climatic regions of the native range were tested using degree day models. This showed that each population’s thermal physiology matched their particular climate. However, after years of being reared under the same conditions in quarantine, experiments showed that their thermal physiologies have converged, which may be the result of adaptation or thermal plasticity. Samples of E. catarinensis have been collected from the hottest and coldest establishment sites in South Africa. Thermal plasticity will be investigated by determining their critical and lethal thermal limits. This will be done in summer and winter for comparison. Thermal limits will be tested before and after cold hardening using E. catarinensis from the BCRG mass rearing facility. Preliminary results have shown that insects from the colder site have lower thermal tolerances compared to those of the warmer site. If the thermal physiology of E. catarinensis has the ability to change due to phenotypic plasticity then it would be beneficial to exploit that characteristic, thus increasing their chances of establishment in colder regions. This will be done through cold hardening during mass rearing. 

Read 2955 times Last modified on Tuesday, 03 May 2016 12:12

General News Updates

2019 National Symposium on Biological Invasio…

26-02-2019

This is your invitation to South Africa's 2019 National Symposium on Biological Invasions. The convention is hosted by the Centre for Invasion Biology (CIB), University of Stellenbosch, and the Biolo... Read more

2019 Invasive Species Training

22-01-2019

During the past five years (2014-2018), ISSA invasive species trainers have trained 4 000 in the identification of invasive species and laws pertaining to invasive species across South Africa.  ... Read more

Alien Grass Working Group

04-09-2018

Who are we? The South African National Alien Grass Working Group was jointly initiated by the South African Biodiversity Institute (SANBI) and the Centre for Excellence in Invasion Biology (C·I·B) in... Read more

Permits for planting indigenous Cynodon?

01-03-2018

On 16 February, 2018, South Africa's Department of Environmental Affairs issued amendments to the regulations and lists relating to the National List of Invasive Species.  Updates to the draft&n... Read more

Invasive species training 2018 dates released

28-02-2018

Interested in invasive species?  How much do you know about NEMBA invasive species compliance for landowners and organs of state? The South African Green Industries Council (SAGIC) have released... Read more

Communications post for Africa advertised

25-01-2018

The Nature Conservancy has advertised a brand new post:  Communications Manager, Africa Region. Knowledge of invasive species and water would be an asset in this post. See details below:    Job Titl... Read more