Adult dogbane beetles are iridescent blue-green beetles with copper-colored shine on their front wings. The legs and antennae are really dark blue that is almost black. Their heads and upper parts of their bodies have small, deep holes. They have long antennae between their eyes that have 12 joints each. Their front mouthparts, called mandibles, are flat and adapted to eating plants. The left side is longer, and actually fits into a groove on the right. Their mouthparts are also adapted to lapping up juice from milkweed plants. Dogbane beelte larvae have white bodies and brown heads. (Blatchely, 1926; Wilson, 1934)
Dogbane beetles are found wherever the plants they live on are found. Most often, they feed and live on dogbane plants, especially Indian hemp and spreading dogbane. Indian hemp is found throughout the entire United States and is often thought of as a weed. It prefers open habitats where it can spread. It lives along the side of roads, fields, railroad tracks, lakeshores, and places that have been disturbed. Spreading dogbane is found in the northeastern United States. Spreading dogbane lives in forests, at the edge of forests, along the banks of streams, and in fields with sand or gravel soil. (Dobler and Farrell, 1999; Peterson, et al., 2001; Schultz and Burnside, 1979; Wilson, 1934)
Larvae in the first stage of development, or first instar, hatch from eggs in midsummer. They burrow into the soil and eat the roots of the plant they live on. They develop in a chamber in the soil, and wait for their bodies to harden before they dig their way back up to the surface. Adult dogbane beetles mate and lay eggs during the rest of the summer. (Peterson, et al., 2005)
Dogbane beetles mate about once a day, usually early in the day. Males search for and choose females to mate with. After mating, males ride on the backs of the females to guard them. Dogbane beetles have more than one mate. In the West, dogbane beetles sometimes mate and cross with cobalt milkweed beetles. The mixed beetles are blue-green to brown-purple, but are not able to reproduce. (Peterson, et al., 2001; Peterson, et al., 2005; Schwartz and Peterson, 2006)
Dogbane beetles lay eggs on leaves and stems of the plants where they live or on nearby plants. They lay eggs in large groups of cases, called capsules, that are usually 3 mm wide by 2 mm tall. (Peterson, et al., 2005; Zabriskie, 1895)
Female dogbane beetles lay eggs in capsules, which are cases that protect them. The eggs are left on plants to develop and hatch by themselves.
Adult dogbane beetles emerge in early summer and live as adults for 6 to 8 weeks. (Peterson, et al., 2005)
Dogbane beetles live in small groups in different places because they cannot travel very far and are not very good at colonizing new places. (Williams, 1992)
Dogbane beetles move between plants within a particular area of plants it lives on.
Leaf beetles use visual, chemical, and scent information about their environment when moving into their host plant. Dogbane leaf beetles use chemical signals to communicate with each other in mating. The chemicals are specific to dogbane leaf beetles, and make it less likely that they would mate with other beetles like cobalt milkweed beetles. (Fernandez and Hilker, 2007; Peterson, et al., 2007)
Dogbane beetles mostly eat dogbane plants, usually Indian hemp and spreading dogbane. They also eat milkweed. To protect themselves from being eaten, dogbane plants give off a milky liquid that dries and makes the mouthparts of insects sticky. Dogbane beetles eat the outside parts of the leaves that have less latex and also rub it off on the leaves. They leave sticky bits of latex on dogbane plants. Dogbane beetle larvae mostly eat the roots of the same plants. (Peterson, et al., 2001)
Dogbane plants that dogbane beetles eat have contain chemicals called cardenolides, which partially protect them from diseases and animals. Cardenolides are bitter and toxic to insects. However, many insects that eat plants have adapted to be able to consume and store these chemicals in their bodies. If the beetle is bothered, it releases the chemicals, which puts off predators. Larvae that have a lot of these chemicals are not bothered as much by parasitic wasps. (Dobler, et al., 1998; Dobler, et al., 2011; Labeyrie and Dobler, 2003)
There are no known negative economic impacts of dogbane beetles on humans.
There are no known positive economic impacts of dogbane beetles on humans.
Dogbane beetles are not endangered.
Jaclyn Tolchin (author), University of Michigan Biological Station, Catherine Kent (editor), Special Projects.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
living in landscapes dominated by human agriculture.
having colors that act to protect the animal, often from predators. For example: animals that are bright red or yellow are often toxic or distasteful, their colors discourage predators from eating them.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends.
uses smells or other chemicals to communicate
a period of time when growth or development is suspended in insects and other invertebrates, it can usually only be ended the appropriate environmental stimulus.
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
union of egg and spermatozoan
an animal that mainly eats leaves.
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
Referring to a burrowing life-style or behavior, specialized for digging or burrowing.
An animal that eats mainly plants or parts of plants.
fertilization takes place within the female's body
A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
chemicals released into air or water that are detected by and responded to by other animals of the same species
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).
scrub forests develop in areas that experience dry seasons.
breeding is confined to a particular season
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
living in residential areas on the outskirts of large cities or towns.
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
Living on the ground.
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
uses sight to communicate
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