Warbles of the Tree Squirrel Bot Fly |
| After a larva has chosen a subcutaneous site, it begins to cut through the animal's skin with its two pointed mouth hooks. This image shows blood on a gray squirrel's hide as the bot creates the warble pore. Note that some of the animal's fur is missing, due to scratching of the area by the squirrel. |
|
| The warble, one week after the larva has cut the warble pore, forms a moderately sized lump in the squirrel's skin, as shown in this image. Excrement from the larva, whose pale white posterior end is protruding naturally from the warble pore, and possibly host body fluid, mats the squirrel's fur. |
| During the second week, the warble expands considerably, tightly stretching the squirrel's skin. This 2-week-old warble protrudes prominently from the body of the squirrel. |
| During the third week of development, the warble continues to stretch the animal's skin as the larva within approaches its maximum size. In the lower portion of this image, the darkened posterior end of the nearly mature larva can be seen filling the pore of the 3-week-old warble. Two days after this photo was taken, the larva backed out of the warble and dropped to the ground, where it burrowed into the soil to pupate. |
| After a larva has exited its warble, the squirrel is left with a gaping warble pore, as seen in this image. However, healing generally occurs relatively rapidly; within about a week the size of the warble has decreased considerably and the warble pore has healed shut. Eventually, the swelling subsides and the animal's fur grows back, leaving little or no sign of the previous infestation. |