The ABCs of observing arthropods / insects

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A: Learn to move slowly, without making sudden movements.

Once the insects are spotted, the real detective work begins. What are they doing? What are they busy doing? Among the main behaviors of insects, there are those related to:

  • food  : eat or look for food;
  • locomotion: moving by flying, jumping, walking, swimming;
  • communication: showing your colors, emitting smells, dancing like bees do;
  • reproduction  : look for a mate, do a courtship display, mate, lay eggs;
  • defense: to hide, flee or attack an enemy, defend its territory.

Living insects are sometimes caught in order to observe them better. However, it is always best to release them where they were captured after observations are complete.

B: Sharpen your gaze, and even try to “see” differently, looking for very small clues.

C: Stay alert and listen: some insects reveal their presence with a sound or rapid movement.

Are there more or less this year?

Are there more ants, mosquitoes this summer? Butterflies seem less numerous than in past years? Are spiders more abundant? These issues usually arise in early summer for ants and mosquitoes, and early fall for social wasps. But what is it really?

Whether it is mosquitoes, ants, wasps or butterflies, it is next to impossible to know if these insects are more numerous from year to year. To do this, researchers would have to follow the evolution of their populations from year to year in the different regions. Some important insect pests, such as the spruce budworm, deserve such attention because of their impact on our economy. However, this is not the case with insects considered beneficial (apart from their bites or disturbing behavior) and not causing damage to market garden crops or the forest industry.

When to observe insects?

A multitude of insects jump, fly, run, crawl and swim during the hot season. Depending on the species, the temperature, the degree of humidity and sunshine, as well as the force of the wind, they are activated at night or during the day, in the evening or in the morning, or all day long.

When you find a site of interest, do not hesitate to return to it several times during the year. Thus, you will discover the species which succeed each other over the seasons or observe the stages of development of the same species, from egg to adult.

Where do they hide during the cold season?

What do insects do during the winter when it is too cold to feed and multiply? Are they leaving us for more lenient skies? If not, where do they hide during these long cold months?

Some go away, but most stay!

With the exception of the monarch, all of our insects stay in Quebec in the winter. Depending on the species, they spend the cold season at the egg, larva, pupa or adult stage. Some, such as cicadas and ants, burrow into the ground and thus avoid freezing. Others, including future queens of bumblebees and social wasps, survive isolated, hidden in leaf litter, under piles of bark or in crevices in rocks. In mosquito species of the genus Aedes , the eggs spend the winter hidden under the ice of ponds. Very early in the spring, when the water most exposed to the sun is thawed, we can also see a few larvae grazing on the algae under the surface of the dead leaves.

How do insects survive the winter?

Arthropods, including insects, are cold-blooded animals, that is to say organisms whose vital functions such as food, motor skills, reproduction, depend on the ambient temperature. For this reason, they are very vulnerable to drastic drops in winter temperatures. Also, to get through the cold season, arthropods have developed adaptations essential to their survival.

An ingenious strategy

Usually, the process of adapting to winter takes weeks and begins when the days get shorter, towards the end of summer. In addition to waiting for the warmer temperatures of the following spring to complete the stages of their development , insects and other arthropods reduce the amount of water their bodies can contain. In addition, they accumulate in their blood, called hemolyphe, small molecules of glycerol which they use as antifreeze during the winter. With the onset of extreme cold, they enter “diapause”, ie in a state of almost metabolic inactivity.

Glycerol is a kind of alcohol that prevents the breakdown of cells in the body. It has the effect of preventing the water in the body from freezing and producing ice crystals which would tear cell walls and cause the body to die. By preventing water molecules from crystallizing inside their tissues, arthropods greatly increase their chance of survival. They can withstand temperatures as cold as –30 ° C and sometimes even higher.

If they were to end up here by accident, tropical species that do not have this ability to resist the cold, would not manage to survive the winter.

Where to observe them?

There are insects almost everywhere. No need to prepare for a real safari to see them at work; fascinating finds can be made in our courtyard or on our balcony. However, when visiting habitats as diverse as an urban park, a field, a garden, a marsh, we notice that different insects often have preferences for one or the other of these environments. In addition, the edge of the field and the forest often shelters species belonging to both environments. This particularity makes it a site of choice for observation.

Plan your exit

Some insects can be difficult to see, for example if they move very quickly, if they live in water, or if they are active at night. Also, to better observe them, you must take the time to properly prepare your expedition.

Depending on the objectives and the duration of an outing, the field equipment will be different. Interesting observations can be made without any material. However, there are a few things that can make our job easier.

A notebook and …

It’s the best way to remember the bug that caught our eye. Write down the place, date and time of the observation as well as the behaviors observed, the weather, the type of habitat. If the insect is on a plant, it can be identified. Adding photos, drawings or a diagram can also be helpful.

… if needed :

  • one or more insect and plant identification guides ;
  • a pocket knife, always useful for lifting bark, for example;
  • pliers, to handle small insects or those you hesitate to touch;
  • a magnifying glass which can be suspended from the neck or integrated into a small transparent box containing the insect, the time of the observation;
  • a net or other capture device, such as plastic containers, to temporarily catch an insect, observe it and then release it.
  • a few plastic bags, of the “ziploc” type, to bring back leaves or flowers of host plants for identification purposes.
  • a hat, long-sleeved shirt and pants are often required to protect against mosquitoes, sun, rain and thorny plants.

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