American spider beetle
Encyclopedia
The American Spider Beetle is a scavenger found in various locations around the world. It is generally seen as a pest that needs to be exterminated as they can be found feasting on a large variety of foodstuffs wherever they are stored. Often mistaken for being part of the order Araneae for its spider
-like appearance, it is actually part of the order Coleoptera. This beetle is notable for its survival in extreme conditions like desiccation and freezing temperatures.
. The prothorax is constricted at the base of the elytra. It tends to be pear-shaped and convex, with its elytra appearing swollen, giving the impression of a glass bead with legs. The antennae
and legs are long and slender, which give it a spider-like appearance, and these tend to be pale brown to yellow. The antennae are filamentous, and arise on the front of the head where they are close together at their base. The segmented abdomen
is covered in long hairs. Larva are grub-like, with short legs and cream-coloured bodies.
s, the American spider beetle has holometabolous development. The beetles usually appear in the spring. The female will lay approximately 40 eggs on or in proximity to a food source, often grain. The eggs are spindle-shaped and very small. Eggs hatch into larva
e which reach about 1/8 of an inch in length. Development takes about 3 months with 3 molts before a pupal phase. The larva can over-winter in this pupal cell with pupation occurring the following spring. There may be one to two generations per year, depending on the ambient temperature and humidity.
or animal matter, and even wool
s and textiles. All types of grain
and grain-products are consumed as well as nuts, animal skins, beans, paper and wood, cacao and chocloate, dead insects and other animals, dried fruit and vegetable matter, excement, feathers and hair, and some living plants. It also has a taste for the exotic, dining on such items as cayenne pepper, tobacco and opium. These plants contain chemicals which would be toxic to many other species.
The beetle is able to survive without drinking water for over seven years. Spiracle
s that open internally aid in this incredible feat. This moisture-retaining adaptation is usually restricted to desert species, but the spider beetle uses it to live in extremely dry stored grain. The beetle can also reclaim water from its own urine
. It is truly an efficient water-user.
Even food is a luxury the spider beetle can do without. When food is scarce, an adult can enter quiescence
– a period of inactivity where it hardly moves and would appear dead to the unknowing observer. When conditions improve, the beetle comes out of its “suspended animation” to feast.
The American spider beetle is certainly a marvel of nature – a living testament to the power of evolution to create creatures that will survive under the harshest of conditions.
The beetles typically forage at night and thus are rarely seen. They can be active in temperatures below freezing.
. In addition, thoroughly clean storage facilities beforehand by use of a strong suction vacuum cleaner to eliminate favorable development places. Inspect stored foods routinely and eliminate any dampness or high humidity conditions. Eliminate rodents, birds, and other insects as spider beetles feed on feces and dead insects.
Spider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...
-like appearance, it is actually part of the order Coleoptera. This beetle is notable for its survival in extreme conditions like desiccation and freezing temperatures.
Identification
The American spider beetle (Mezium americanum) is about 3 mm in length. Its body is dull yellow, with a glossy black elytra. The beetle has blunt projections on each side of an almost cylindrical thoraxThorax
The thorax is a division of an animal's body that lies between the head and the abdomen.-In tetrapods:...
. The prothorax is constricted at the base of the elytra. It tends to be pear-shaped and convex, with its elytra appearing swollen, giving the impression of a glass bead with legs. The antennae
Antenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....
and legs are long and slender, which give it a spider-like appearance, and these tend to be pale brown to yellow. The antennae are filamentous, and arise on the front of the head where they are close together at their base. The segmented abdomen
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
is covered in long hairs. Larva are grub-like, with short legs and cream-coloured bodies.
Distribution
Mezium americanum is a cosmopolitan species, but is an exotic species in Australia.Life cycle
Like other beetleBeetle
Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...
s, the American spider beetle has holometabolous development. The beetles usually appear in the spring. The female will lay approximately 40 eggs on or in proximity to a food source, often grain. The eggs are spindle-shaped and very small. Eggs hatch into larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e which reach about 1/8 of an inch in length. Development takes about 3 months with 3 molts before a pupal phase. The larva can over-winter in this pupal cell with pupation occurring the following spring. There may be one to two generations per year, depending on the ambient temperature and humidity.
Diet
Food is often grain, but the spider beetle also eats dried vegetableVegetable
The noun vegetable usually means an edible plant or part of a plant other than a sweet fruit or seed. This typically means the leaf, stem, or root of a plant....
or animal matter, and even wool
Wool
Wool is the textile fiber obtained from sheep and certain other animals, including cashmere from goats, mohair from goats, qiviut from muskoxen, vicuña, alpaca, camel from animals in the camel family, and angora from rabbits....
s and textiles. All types of grain
GRAIN
GRAIN is a small international non-profit organisation that works to support small farmers and social movements in their struggles for community-controlled and biodiversity-based food systems. Our support takes the form of independent research and analysis, networking at local, regional and...
and grain-products are consumed as well as nuts, animal skins, beans, paper and wood, cacao and chocloate, dead insects and other animals, dried fruit and vegetable matter, excement, feathers and hair, and some living plants. It also has a taste for the exotic, dining on such items as cayenne pepper, tobacco and opium. These plants contain chemicals which would be toxic to many other species.
Behaviour and adaptations
Unlike most beetles, spider beetles cannot fly because their wing-coverings (elytra) have fused to create a solid, hard shell. This one-piece suit prevents the insect from losing water – an important trait for living in dry environments.The beetle is able to survive without drinking water for over seven years. Spiracle
Spiracle
Spiracles are openings on the surface of some animals that usually lead to respiratory systems.-Vertebrates:The spiracle is a small hole behind each eye that opens to the mouth in some fishes. In the primitive jawless fish the first gill opening immediately behind the mouth is essentially similar...
s that open internally aid in this incredible feat. This moisture-retaining adaptation is usually restricted to desert species, but the spider beetle uses it to live in extremely dry stored grain. The beetle can also reclaim water from its own urine
Urine
Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...
. It is truly an efficient water-user.
Even food is a luxury the spider beetle can do without. When food is scarce, an adult can enter quiescence
Quiescence
Quiescence may refer to:*Quiescence search, in Game searching in artificial intelligence, a quiescent state is one in which a game is considered stable and unlikely to change drastically the next few plays...
– a period of inactivity where it hardly moves and would appear dead to the unknowing observer. When conditions improve, the beetle comes out of its “suspended animation” to feast.
The American spider beetle is certainly a marvel of nature – a living testament to the power of evolution to create creatures that will survive under the harshest of conditions.
The beetles typically forage at night and thus are rarely seen. They can be active in temperatures below freezing.
Human Impacts
Common infestation sites in a house can also be wall voids and drop ceilings. Hence, this beetle can not only damage certain food products but also can damage the house. As a pest species, this beetle is subject to extermination whenever an infestation is found. A few methods of extermination includes heating the infested product to a high temperature, placing it into a deep freezing temperature, microwaves or the use of insecticides that use a chemical compound called a pyrethroidPyrethroid
A pyrethroid is an organic compound similar to the natural pyrethrins produced by the flowers of pyrethrums . Pyrethroids now constitute a major commercial household insecticides...
. In addition, thoroughly clean storage facilities beforehand by use of a strong suction vacuum cleaner to eliminate favorable development places. Inspect stored foods routinely and eliminate any dampness or high humidity conditions. Eliminate rodents, birds, and other insects as spider beetles feed on feces and dead insects.