ENTM 340 Insect Pests of Trees Turf and Ornamentals�

�C. Sadof� Purdue University

Lecture 1� Introduction to Course and Study of Arthropods

 

  1. Introduction - Syllabus and Course Requirements

a.       Course objectives and topical organization

                                                               i.      Basic entomology

1.      Insect structure and function

a.       Basic anatomical characteristics of insects,

b.      How anatomy influences how insects attack plants

c.       How anatomy affects insect classification and relation to other arthropods

d.      Basic life system processes, reproduction, digestion circulatory molting.�

e.       Use a key to identify Orders of major economic pests (beetle, fly, butterfly , bug, etc)

2.      Understand principles of population growth and regulation

3.      Applying �principles to develop and meet appropriate management objectives

                                                             ii.      Diagnosis, biology and management of pest guilds

1.      Learn how to use symptoms and signs to diagnose insect pests of woody plants, herbaceous perennials and flowers

2.      Make a collection of 25 insect injury specimens to get field experience

                                                            iii.      Managing pests in turf and ornamental systems

1.      Learn details of managing key landscape and production systems.

    1. Grading

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    1. Collection of 25 specimens

 

Basic Entomology�

 

a. Important Links

John Meyer�s Basic Entomology Tutorial� from North Carolina State University http://www.cals.ncsu.edu:8050/course/ent425/tutorial/index.html

 

Dave Shetlar�s Course on Insects of Ornamentals from Ohio State University� http://bugs.osu.edu/~bugdoc/Shetlar/462/462_intro.htm

 

 

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����� b. Hierarchical classification:� Insects are arthropods, What does this mean?

                                                               i.      Kingdom

                                                            ii.      Phylum-- Arthropoda

                                                            iii.      Class

                                                           iv.      Order

                                                             v.      Family

                                                           vi.      Genus

                                                          vii.      Species

                                                        viii.       

c. Shared Characteristics of Phylum Arthropoda (Jointed foot)

                                                           ix.      External characteristics

1.      Body covered by exoskeleton formed of cuticle secreted by epidermis (contrast with vertebrates). Arthropods molt, vertebrates don�t.

2.      Bilateral symmetry

3.      Body divided into segments

4.      Pairs of appendages on each segment

a.       Differentiates from Phylum Annelida the segmented worms, which also have repeating body segments. This phylum is ancestral to both Mollusca and Arthropoda.

b.      Onychophorans are the first step in a process known as tagmatization, (Fig. 11.8 Romoser and Stoffalano 1998). These� �missing link� species are related to the Phyla Arthropoda� and Annelida.� Like annelids onychophorans have segmented sections, but like primitive arthropods this group has appendages on each segment.� .Studies of ribosomal RNA sequences suggest that this group is the most ancestral arthropod.

5.      Evolution of segments into functional units or tagma are characteristic of this group.� (eg. Insects have 3 tagma, head, thorax and abdomen)

Internal characteristics (contrast with vertebrates where appropriate)

6.      Dorsal circulatory system, with contractile heart in pericardial sinus that runs through each segment.

7.      Ventral nervous system with 2 trunks and a paired ganglion for each segment.

8.      Linings of stomadaeum (oral cavity) and proctadaeum (anal cavity), tracheae (respiratory tract) and gland ducts are lined with cuticle.

    1. Major Classes of arthropods- Arthropods stem from many evolutionary lines (polyphyletic group).� As such, there is no simple story that tells the progression of arthropods to insects.� For the purpose of this class, I divide arthropods 2 ways.� First by the mouth parts, then, within the mandibulate group, by the number of legs.

                                                               i.      Subphylum Chelicerata (mouthparts are scissor-like chelicerae)

                                                             ii.      Subphylum Mandibulata (mouthparts with pliers-like mouthpart= mandible) (One pair of mandibles + 2 pairs of maxillae)

 

    1. The Chelicerate Arthopod Classes

                                                               i.      Chelicerata (mouthparts are scissor-like chelicerae)

(2 Tagma present = chephalothorax + abdomen)

�Antennae Absent

1.      Class Merostomatta �(Horseshoe crab)

a.       Plate-like gills covering body,

b.      Tail

2.      Class Arachnida� (Spiders) � 8 legs

a.       Order Scorpionida (scorpions)

b.      Order Acari (ticks and mites, including- spider mites) (some pant feeders)

c.       Order Aranea (spiders) (many predaceous)

d.      Order Opilones (Daddy-longlegs)

 

f.� The Mandibulate Arthropod Classes (mouthparts with pliers-like mouthpart= mandible) (One pair of mandibles + 2 pairs of maxillae)

��������������������������� i.� >6 legs (Myriapods)

 

1        Class: Chilopoda� (Chilo=lip; poda �foot) (centipedes)

e.       2 Tagma present: Head + trunk

f.        Legs: One appendage per segment,

2.      Class Diplopoda (Di=two; poda=foot) (millepedes)

a.       2 Tagma present: Head + trunk

b.      Legs: 2 appendages� per segment

3.      Class Crustacea (crayfish, sowbugs, crabs)

a.       2 Tagma present: Have cephalothorax and abdomen)

b.      Legs:� 5-7 pairs of legs

�������������������������������� 6 Legs� (Hexapods)

���������������������� a. Tagma present: Head + thoracic segments that resemble abdomen

4.�� Class Protura (Cone heads).

5.      Class Collembola (Spring tails)

6.      Diplura� (Diplurans)

 

7.      Class Insecta

a.      3 Fully Distinct Tagma present: Head thorax and abdomen

b.      Winged adults (usually).

 

 

Review questions-

  • Name at least 3 external and 2 internal characteristics that arthropods share.
  • How are antennae, legs, and mouthparts related?
  • �Insects are mandibulate, not chelicerate arthropods, like spiders. What essential characteristics of the mouth separate insects and spiders?�
  • Name at least 2 other characteristics that distinguish insect from spiders (hint legs, tagma).
  • Distinguish between a centipede and a millipede based on the number of legs per segment.
  • What proportion of insects are pests?

 

 

References:

Oseto 2001.� Outline of Entomology,

Romoser and Stoffalano 1998, The Science of Entomology