What do insects use to sense their environment?

Another e-mailed question. Besides their eyes that give them a visual representaton of their environment, insects have a wide array of sensory hairs, sensillae, that give them information about temperature, humidity, chemicals, body position, and orientation. Sensillae can be individually distributed, or they can be grouped into sensory fields or …

How long do bees live?

Before answering the titular question, we need to understand how bees work. The head of a bee society is the queen. The majority of the bee colony consists of workers, who do all the menial tasks. A special subcaste of workers are the nurser bees, who are only there during …

Spider Vision

This is a requested post on the basics of spider eyes; for more on spiders, check out my spider lecture. Spiders only have ocelli, simple eyes consisting of a lens covering a vitreous fluid-filled pit with a retina (pigment cells + visual cells) at the bottom. The ocelli come in …

Bryozoan Placentas

Pictured above is Celleporella hyalina, a species of cheilostome bryozoan. Bryozoans are aquatic, filter-feeding, colonial organisms – each opening up there is the house of an individual bryozoan, and they all live together in this colony that can sprawl over any substrate, often playing a significant role as foulers. Each …

Do Insects Have Fat?

Insects have a fat body. It’s a versatile organ, a sort of combination of adipose tissue (the blubber that humans have) and liver. Its principal roles are: As with adipose tissue, it is the main nutrient storage site (Telfer & Kunkel, 1991); Storage of neutralised waste metabolites; Detoxification of ammonia …

How do insects breathe? An outline of the tracheal system

Hexapods (including insects) have two pairs of openings on their thorax, called spiracles. These open into chitinous tubes called tracheae which then further subdivide until becoming less than 1 mm in diameter tracheoles, 2-3 µm away from metabolically-active tissues, forming a network all through the body of the insect, as …

Regeneration

Note that I’m not referring to regeneration in the ecological sense (i.e. recovery of communities). I will also only talk about animals in this post, for the simple reason that regeneration in plants is commonplace and a routine part of their physiology. Of course, any animal with eyes also has …

The Genetics of Ageing: Basics

One of the earliest blog posts I wrote was about ageing. However, it was too convoluted and meandering even by my standards, so I set it to private, pending a rewrite. But I occasionally get questions about ageing, so I might as well do a quick summary.