The Acacia tree serves as a habitat in the desert ecosystem of the Middle East. All parts of the Acacia are eaten by different types of animals and among the few plants that can provide green foliage even in the driest seasons. A genuine oasis for all kinds of living creatures. But the Acacia is also known for the symbiotic relationship between various living creatures. Without the Acacia tree, many of those creatures will go instinct in Israel.
Even after they die they still serve as a habitat. An Acacia tree can stand dead for decades and still provide various functions even after he ended his life cycle. The dead and organic material is used as food for many insects; usually different kinds of beetles; Mostly their larvae. The spaces they leave is used as hiding or as habitat for other arthropods which may devour the smaller insects.
The Acacia and the Dorcas Gazelle
The Tree attracts a range of ungulates (large mammals with hooves) that feed on its leaves and fruits and benefit from its shade during the hot daylight hours. One of these is the Dorcas Gazelle that During the summer months, these gazelles foraging areas overlap the distribution of acacias in the desert. Taking shelter in the trees during the hot hours, the gazelle also eats its leaves and fruit – as a source of both water and food.
The Gazelle, eating the fruits of the Acacia chews only some of the seeds. The seeds that are not chewed, pass through their digestive systems undamaged. Eventually, they are ejected with the gazelle’s droppings. This way the gazelle distributes the seeds of the Acacia tree. The seeds were germinated more successfully than seeds that didn’t pass through the digestive system of the gazelle.
It turned out that the acacia’s hard seed coat is softened in the gazelle digestive system. The softening of the seed coat increases the chances of the seeds to germinate. It has also been found that the digestive gastric acids in the gazelle stomach kill the larvae of sperm beetles (Bruchidae), which develop inside the seeds and harm them.
A fruit infected by the beetle usually won’t be suitable for germination. In some parts of the Negev 90% of the seeds are found to be infected by the beetle. Also, those that do sprout don’t survive due to dehydration or being eaten.
Nectar and Sap – a Celebration for a Variety of Insects
So many insects feed on nectar from the tree’s flowers or sap, as these liquids contain a high concentration of sugar. Some such as Babul Blue Butterfly (Azanus ubaldus) pollinate the acacia as they fly from one tree to another. The Babul Blue entered our region via the Great Rift Valley. The adult butterflies fly around the branches of the Acacia. The butterfly larvae feed on the tree flowers. The Babel Blue is mainly found in the Negev, Beersheba area, Sde Boker.
So the Acacia in the Negev constitutes a unique habitat in Israel, which includes dry tropical conditions, known from Africa. Israel is the Acacia northern boundary limit. The tree provides plenty of food during the harshest time of the year; when other plants or trees are not in reach. As a Habitat it houses a huge variety of animals, some rely almost entirely on the Acacia; Some live on the trees and never leave.