Life history of invertebrates

Stream insects vary in their tolerance to environmental stress in different stages of their life cycle.

Insect species which are known to be sensitive to pollution or habitat change, such as mayflies (Ephemeroptera), stoneflies (Plecoptera)or caddisflies (Trichoptera) may have certain life history stages that could be more resistant to the stresses involved with reintroduction. Using the most resistant life history stage for invertebrate, reintroduction may decrease stress and/or mortality rates.

Acanthophlebia exuvae: remains of an insect's exoskeleton.

Insect developmental processes and life history differ depending on the type of insect. One stage of the life cycle may be more suitable for reintroduction than another, and so it is important to know detailed information on developmental processes on the target insect species. For example, insects which show signs of incomplete metamorphosis (e.g. mayflies and stoneflies) have larvae that bear resemblance to the adult form, but lack wings. Wing buds are usually visible on the thoracic segments, and are relative in size to the age of the larva. In most cases, when the wing pads are dark and large, the insect will be close to maturity and therefore possibly more suited for collection, transportation and reintroduction.

Sample collection: artificial substrates

Adult insect emergence and flight period need to be carefully considered, so that species are not released at the wrong time of the year or too late in the flight period to effectively mate and reproduce. This is particularly relevant to typically short-lived groups such as mayflies. Aquatic insect flight period may also depend on latitude or altitude of the restoration site as flight or emergence periods for the same species may be longer in the warmer northern regions of New Zealand, but more restricted in southern or alpine regions.

a biological process which allows an animal to change from one form to another after birth or hatching, such as a caterpillar turning into a butterfly. This is a relatively fast process which involves cell growth and differentiation. belongs to the thorax, which is a division of an animal's body that lies between the head and the abdomen.the time of year and duration of time an insect is mobile in the air.