Among the Arthropods

         Welcome to Among the Arthropods, a database of common arthropods of East Central Illinois.   This database was developed by Elise Lauterbur and Rachel Sandretto, a pair of students at University Laboratory High School in Urbana, Illinois, as an alternative to the standard Field Biology course offered there.  "Bug Bio" (as it's known) involves creating a collection of arthropods.  While both students had great interest in the idea, neither desired to learn about it in a manner that would harm their subjects.  Thus, this photographic database was created.

Phylum Arthropoda

        Phylum Arthropoda contains the largest number of organisms of any phylum in the Kingdom Animalia, totaling in the millions.  Despite the enormous diversity found among them, they all share the following common characteristics:

1)    They have segmented bodies.

2)    All possess paired, segmented appendages on every segment, be it antennae, wings, legs, or others types.  Many arthropods lose some of these appendages once they are adults.

3)    They have bilateral symmetry, meaning that the right and left sides of their bodies are mirror images of each other.

4)    All possess a hard exoskeleton of chiton, which they have to shed in order to grow.

5)    They have a well-developed digestive system with tubular alimentary canals, which prevent the mixing of food and waste.

6)    All possess an open circulatory system, which means that their blood sometimes moves freely throughout their bodies instead of being directed through blood vessels.

7)    They all have similar respiratory systems, with small openings on their sides, leading to trachea and tracheoles, where gas exchange occurs.

Subphylum Mandibulata:

    These arthropods get their name from having mandibles, which are chewing and grinding mouthparts, instead of chelicerae, though they are vestigial in some members which have siphoning or piercing and sucking mouthparts as primary feeding appendages.  They can have from six to hundreds of legs.  All possess one or two pairs of antennae.  They have either two or three body segments, which can have a variety of names.    Some common members of this subphylum include crustaceans, millipedes, centipedes, and insects (also known as hexapods.)

Subphylum Chelicerata: 

    Members of this subphylum are defined by the presence of chelicerae, more commonly known as fangs.  Behind the fangs are two pedipalps, club-like appendages used for gripping their mates and their prey.  They possess four pairs of walking legs, but have no antennae.  They have two body segments, a cephalothorax (a fused head and thorax,) and an abdomen.  Some common members of this subphylum are spiders, harvestmen (daddy longlegs,) ticks and mites, scorpions and pseudoscorpions.