Food Uptake And Utilization

their nest. Parasitic insects, too, exhibit various degrees of host specificity. Thus, cer- 489

tain sarcophagid flies parasitize a range of grasshopper species; the common cattle grub (Hypoderma lineatum) is typically found on cattle or bison, rarely on horses and humans; lice are extremely host-specific, as would be expected of sedentary species.

The termination of feeding (assuming that food supply is not limiting) is largely related to the amount of food ingested and the stimulation of strategically located stretch receptors. In locusts, for example, the filling of the crop is measured by receptors at the anterior end that send signals to the brain via the stomatogastric system. In flies both crop- and esophagus-filling are important in bringing feeding to a close, while in female mosquitoes and, probably, Rhodnius prolixus the signals arise from stretch receptors located in the abdominal wall, which is greatly distended after a blood meal. Other factors that may play a minor role in terminating feeding are adaptation of the chemosensilla on the mouthparts and a change in the osmotic pressure or composition of the hemolymph as absorption of digested materials occurs (see chapters in Chapman and de Boer, 1995).

Apart from the specific cues outlined above that facilitate location and selection of food, there are other factors that influence feeding activity. Typically, insects do not feed shortly before and after a molt, or when there are mature eggs in the abdomen. In addition, a diurnal rhythm of feeding activity may occur, in response to a specific light, temperature, or humidity stimulus. For example, the red locust (Nomadacris septemfasciata) feeds in the morning and evening, and many mosquitoes feed during the early evening (though this may change in different habitats). Pupae, most diapausing insects, and some adult Ephemeroptera, Lepidoptera, and Diptera do not feed.

Beekeeping for Beginners

Beekeeping for Beginners

The information in this book is useful to anyone wanting to start beekeeping as a hobby or a business. It was written for beginners. Those who have never looked into beekeeping, may not understand the meaning of the terminology used by people in the industry. We have tried to overcome the problem by giving explanations. We want you to be able to use this book as a guide in to beekeeping.

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