Parasitism and Acacia Trees
November 25, 2016
Photographer: Menashe Davidson
Summary Author: Menashe Davidson
The umbrella thorn acacia (Vachellia tortilis) grows under extremely arid conditions. It can tolerate drought, high temperatures and the stony soils characteristic of the southern Negev region of Israel. On a tour of the Timna Park area of Israel in late summer, I noticed the very poor appearance of the acacia trees -- brown color and bare twigs. However, as I walked my eyes were attracted to green leaves among the pale twigs of the acacia (top photo). Even in their poor condition, they served as a host to a parasitic plant that grows and feeds on acacia trees here. The parasite plant known as the acacia strap flower (Loranthus acacia) is a green parasite. Carbon dioxide is converted to carbohydrates through photosynthesis as it sucks at the water and nutrients of its host. When I approached closer, I could detect the small pink-red flowers of this parasitic plant. In the bottom photo, the stems of the strap flower (the darker stems in the photo) can be seen twisting along the host branches. Most all of the acacias are hardy enough to survive not only their uninvited guests but also the harsh environment of the Negev Desert. Photo taken on September 16, 2016.
Photo Details: Top - Camera Model: NIKON D7100; Focal Length: 26mm (35mm equivalent: 39mm); Aperture: ƒ/20.0; Exposure Time: 0.0031 s (1/320); ISO equiv: 640; Software: Windows Photo Editor 10.0.10011.16384. Bottom - same except: Focal Length: 70mm (35mm equivalent: 105mm);
Exposure Time: 0.0080 s (1/125); ISO equiv: 500.