Gazelle : The Palestinian Biological Bulletin (ISSN 0178 – 6288) . Number 116, August 2014, pp. 1-23. | Page 12

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ْ َ َ ُ ْ ُْ ُ َ
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ٌ ُ ٌ َ َ ُْ َ ِ
. 7 ‫خشعًا أَ ْبصارهم ٌَخرجُون مِن اْلَجْ دَاث كؤ ََّنهم جراد م ْن َتشِ ر . سورة القمر ، اآلٌة‬

Desert Locust (Schistocerca gregaria) on Al-Ka’ba Kiswah in Makkah Al-Mukarramah.
Photo by: Prof. Dr. Norman Ali Bassam Khalaf-von Jaffa. 02.01.2014.
http://www.flickr.com/photos/50022881@N00/11837535283/
. ‫الجراد الصحراوي ٌُسبح للرحمن خالق الحٌوان على كسوة الكعبة المُشرفة فً مكة المُكرمة . تصوٌر المإلف‬
. .01.210.22
The desert locust (Schistocerca gregaria) lives a solitary life until it rains. Rain
causes vegetation growth and allows the female to lay eggs in the sandy soil. The
new vegetation provides food for the newly hatched locusts and provides them
with shelter as they develop into winged adults (Wikipedia).
When vegetation is distributed in such a way that allow the nymphs, usually
called hoppers, to congregate, and there has been sufficient rain for most eggs to
hatch, the close physical contact causes the insects' hind legs to bump against one
another. This stimulus triggers a cascade of metabolic and behavioral changes
that cause the insects to transform from the solitary form to the gregarious form.
When the hoppers become gregarious, they change from green-coloured to
yellow and black, and the adults change from brown to red (immature) or yellow
(mature). Their bodies become shorter, and they give off a pheromone that
causes them to be attracted to each other, enhan cing hopper band and
Gazelle : The Palestinian Biological Bulletin – Number 116 – August 2014