Symbiotic ants as an alternative defense against giraffe herbivory in spinescent Acacia drepanolobium
We explore here the occurrence of aggressive ants in an apparently symbiotic relationship with the savanna tree Acacia drepanolobium and their effects on giraffe herbivory on the Athi-Kapiti Plains, Kenya. Trees taller than 1.3 m were more likely to be occupied by aggressive ants in the genus Crematogaster than were shorter trees. Ants were concentrated on shoot tips, the […]
Condensed tannin as anti-defoliate agent against browsing by giraffe (Girafla camelopardalis) in the Kruger National Park
The feeding behaviour of giraffes in the Kruger National Park, South Africa, was observed over 12 months and the diet analysed for condensed tannin content. Supportive evidence was found for plant defence against excessive browsing by means of tannin biosynthesis. Condensed tannin negatively influenced acceptability and nutritional value of dietary browse to giraffes. The giraffes […]
Inducible defences in Acacia sieberiana in response to giraffe browsing
Acacia trees comprise a principal component of the diet of many African browsers. The resultant browsing pressure has led to the evolution of both physical and chemical responses in Acacia trees. In an observational study, we investigated the physical and chemical defenses in Acacia sieberiana var. woodii in response to different intensities of giraffe herbivory. […]
Not all ants are equal: obligate acacia ants provide different levels of protection against mega-herbivores
In obligate ant–plant mutualisms, the asymmetric engagement of a single plant species with multiple ant species provides the opportunity for partners to vary in their behaviour. Variation in behaviour has implications for the interactions with third-party species such as herbivores. This study assessed the effect of obligate ant mutualists (Crematogaster mimosae, Crematogaster nigriceps and Tetraponera […]