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  1. 1. A little bit of… INSECTS August, 2013. (1rst. part) Raimundo Sepúlveda V. IPM-Agronomist, U. de Chile. CHILE (South America)
  2. 2. Introduction… There are many forms to tackle the great topics of INSECTS. A classics way is starting with biodiversity of our planet (huge numbers, different types); another it could be studying the fossil register with first insects (perhaps with mistakes); or simply to talk about the successfuly 6 legs-animals (hexapodes) that live everywhere. Whatever be the beginning, Insects are special animals that have known to colonize Earth since aprox. 400 millions years; even us, the modern man, has not did this. So, we must look and observe Insects with attention, respect and fascination.
  3. 3. Figure 1. A “7 pointed-ladybug”, a good example of insect. Look its body divided in 3 parts and 6 legs (1). 3
  4. 4. General ideas… Entomology is the science that studies Insects and its specialist it is called entomologist. In general, with some exceptions, an Insect has 3 parts: 1) Head, 2) Thorax y 3) Abdomen. For this reason, some scientists call them “three segmented animals” (in 3 sections). The general rule says that they have a external skeleton (exo- skeleton) of chitin; besides, they have 2 antennas, 6 legs when are adults and 4 wings, as maximum. Colours and designs show a great variety and they are related to their habitats or living places. Sizes= a very wide range. Insects are 0,25mm up to 360mm long, aprox. See Figure 2.
  5. 5. Figure 2. A “peach (tree) green aphid”. We see its winged phase with long antennas and legs (2). 5
  6. 6. Classification… All Sciences need Classification (taxonomic or systematics) because classification put things in order and this make the study easier. However, there are many kinds of classifications and the selected-one depends on what we are looking for. In Entomology, we usually prefer and remember the design of insects wings, using the greek word “pteron” (=wing). Then, with this, entomologists created categories, such as: Coleoptera (coleos+pteron) and Lepidoptera (lepidos+pteron), that include (in the same order) “beetles” and “butterflies”. See Figure 3.
  7. 7. Figura 3. A beauty “silvered blue butterfly” (Heliconius sp.). It is clasificated into Lepidoptera, due to its 4 wings with little and coloured scales (3). 7
  8. 8. Final comments… Entomologists have named, at least, a million of Insects. Others scientists have said “for each person on Earth, there are millions or billions of insects”. So, we could conclude that human beings are living on the planet of Insects!. Have a good day… (to be continued)
  9. 9. Images credits… 1.- 2.- 3.- Recommended links… 1.- 2.- Recommended books (in Spanish)… 1.- Peña, L. 2007. Introducción al estudio de los Insectos de Chile. Ed. Universitaria. Santiago, Chile. 264p. 2.- Sepúlveda, R. 2013. Apuntes de la Cátedra “Técnicas de Control de Plagas y Enfermedades…” UTCh-Inacap. Santiago, Chile. 117p. 9