Biologists have long been interested in the occurrence of insects at the extremes of the Earth, in surprising diversity and sometimes in large numbers. Holometab-olous insects are abundant in refugial sites within 3° of the North Pole. Fewer insects, notably a chironomid midge and some penguin and seal lice, are found on the Antarctic proper. Freezing, high elevations, including glaciers, sustain resident insects, such as the Himalayan Diamesa glacier midge (Diptera: Chirono-midae), which sets a record for cold activity, being active at an air temperature of —16°C. Snowfields also

Freeze tolerance

Freeze-tolerant insects include some of the most cold-hardy species, mainly occurring in Arctic, sub-Arctic, and Antarctic locations that experience the most extreme winter temperatures (e.g. — 40 to — 80°C). Protection is provided by seasonal production of icenucleating agents (or INAs) under the induction of falling temperatures and prior to onset of severe cold. These proteins, lipoproteins, and/or endogenous crystalline substances such as urates, act as sites where (safe) freezing is encouraged outside cells, such as in the hemolymph, gut, or Malpighian tubules. Controlled and gentle extracellular ice formation acts also to gradually dehydrate cell contents, and thus avoid freezing. In addition, substances such as glycerol and/or related polyols, and sugars including sorbitol and trehalose, allow supercooling (remaining liquid at subzero temperature without ice formation) and also protect tissues and cells prior to full ice-nucleating agent activation and after freezing. Antifreeze proteins may also be produced; these fulfill some of the same protective roles, especially during freezing conditions in fall and during the spring thaw, outside the core deep-winter freeze. Onset of internal freezing often requires body contact with external ice to trigger ice nucleation, and may take place with little or no internal supercooling. Freeze tolerance does not guarantee survival, which depends not only on the actual minimum temperature experienced but also upon acclimation before cold onset, the rapidity of onset of extreme cold, and perhaps also the range and fluctuation in temperatures experienced during thawing. In the well-studied galling tephritid fly Eurosta solidaginis, all these

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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