Wednesday, 28 April 2010

The stem reaches about 18 m tall and is about 50cm in diameter at breast height, with internodes 8–10 cm long, the nodal scars conspicuous. There are about 12–18 huge leaves in the crown; they are induplicate, costapalmate, and marcescent in immature individuals, tending to fall under their own weight in trunked individuals. The leaf sheath is about 80–100 × 52–58 cm and has a conspicuous triangular cleft below the petiole, with the margins tending to erode into broad tattered lobes. The petiole is massive, about 5m long in juvenile palms, but shorter in adults and is covered with white wax; it is 10–12cm wide near the base and is deeply grooved on the upper surface and rounded beneath, and has smooth margins, completely lacking in spines.

The desert locust's alter ego state occurs when the inhabited desert has a period of rain,

green spots emerge.

Two States of the Desert Locust

1. Solitary, green in colour, subdued. Normal state

2. Gregarious State: Enlarged, extremely social, swarms and attacks, changes colour and markings

Water moistens the soil, the locusts lay their eggs. Surrounding vegetation grows eagerly sheltering the young demanding the rising population rest and eat. A series of metabolic and hormonal changes ensue, reversing the solitary instinct. Their bodies develop warning marks in black and yellow.

Marcescent, marcescere