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Altica subplicata

What do they look like?

Altica subplicata has an oval body shape. The body is a dark metallic blue color, sometimes with deep violet reflections. Antennae and legs are the same color as the body. The pronotum, the plate behind the head, is square in this species, with a deep groove across it. There is another deep groove between the eyes, which are not big. Females of this species tend to be bigger than males. Larvae of A. subplicata are darkly colored. (LeSage, 1995)

  • Sexual Dimorphism
  • female larger
  • Range length
    5.0 to 6.6 mm
    0.20 to 0.26 in

Where do they live?

Altica subplicata, known as the willow leaf beetle, is found north of Mexico, across the Nearctic region. It ranges from the southern most point of Texas to southern Canada from British Columbia to Quebec. The largest amount of this species is along the Mississippi River and the Great Lakes, spreading west to the Rocky Mountains. (LeSage, 1995)

What kind of habitat do they need?

Altica subplicata lives in sand dune habitats along the Great Lakes and on sand bars in rivers. More beetles are found closer to shore on the Great Lakes, with the amount of beetles present decreasing moving farther away from shore. Beetles are not found on plants further than 16 meters from the shore. Willow leaf beetles are more likely to be found on young dunes than older dunes. (Bach, 1993a; DeSwarte and Balsbaugh, 1973)

How do they grow?

Altica subplicata goes through complete metamorphosis. It begins as an egg, then develops into a larva, then a pupa, and finally an adult. Eggs of A. subplicata are laid in the spring. Larvae hatch after about 7 days, and go through 3 larval stages, called instars, during which the larval instars feed. After about 16 days, the larvae move underground and form pupal cells using mucus secreted by maxillary glands. Larvae use moist sand as a pupation site. The pupal period lasts 1 week or more depending on weather conditions. The adults come out of their pupation site and eat for the rest of the summer. During the first cold nights of fall, adults leave the host plant and find shelter in leaf litter, under stones, logs, and bark. They stay here all winter, which is called overwintering. When spring arrives, adults come out of hiding, find mates, and then lay eggs on host leaves. In total, one generation takes about 34 days to complete from egg to adult. Adults live for awhile after emerging from pupation. (DeSwarte and Balsbaugh, 1973; LeSage, 1995; Rickelmann and Bach, 1986)

How do they reproduce?

Adults become able to mate during winter. After overwintering, the willow leaf beetles appear on plants in early spring. Females do not lay eggs for the first 1 to 2 weeks, starting on the first day that the beetles appear on plants. Adults are very active during this period, flying around host plants looking for mates. To mate, the male mounts on the back of the female. These beetles often mate with more than one other beetle. (LeSage, 1995)

Adults of Altica subplicata emerge from overwintering in the spring, and will wait about a week before reproducing. They then start mating and laying eggs. Females lay eggs horizontally in small groups on the underside of young leaves of host plants, along the leaf veins. Up to 100 eggs can be found in an egg mass and a female can lay more than 400 eggs in a lifetime. In a group of eggs, there are equal amounts of male and female beetles. In the southern part of United States, A. subplicata lays eggs two or more different times during the summmer. In northern states and Canada, A. subplicata lays eggs during only one time of the year. (DeSwarte and Balsbaugh, 1973; LeSage, 1995)

  • How often does reproduction occur?
    Willow leaf beetles produce 2 to 3 generations in southern states, but only 1 generation in Canada.
  • Breeding season
    Willow leaf beetles breed in spring in the northern portion of their range, and may have a second summer generation in the southern portion.
  • Range eggs per season
    100 to 400
  • Range gestation period
    1 to 2 weeks
  • Range age at sexual or reproductive maturity (female)
    31 to 37 days
  • Range age at sexual or reproductive maturity (male)
    31 to 37 days

After laying eggs, parents do not do anything else to help their offspring develop.

  • Parental Investment
  • pre-hatching/birth
    • provisioning
      • female

How long do they live?

A typical generation from egg to adult takes about 34 days. Adults live for a period of time after coming out of pupation. Adults that are still alive when winter starts go into hiding and overwinter, and then start mating and egg-laying again in the spring. (DeSwarte and Balsbaugh, 1973; LeSage, 1995)

  • Typical lifespan
    Status: wild
    2 to 12 months

How do they behave?

Larvae of Altica subplicata feed on willow tree leaves in large groups, and often move from one plant to another. Adults also group together on host plants. They tend to group together more often on host plants that are in areas of high humidity, as well as on plants with taller stems. On dunes in the Great Lakes, they are more likely to be found on the youngest dunes near shore, instead of on older dunes. Similar species that also eat willows, in the subfamily Chrysomelinae, find their host plants by detecting chemicals produced by the plant. Both males and females can fly, though they do not fly long distances as they keep close to shore. Adults become more active and fly more when looking for mates. A. subplicata is most active during the day. (Bach and Carr, 1990; Bach, 1993a; Bach, 1993b; Bach, 1993c; Gannon, et al., 1994; Tahvanainen, et al., 1985)

Home Range

Adult beetles stay close to areas of host plants. In the Great Lakes region these are coastal dunes, where A. subplicata stays almost entirely on the youngest dunes. (Bach and Carr, 1990; Bach, 1993a; Bach, 1993c; Bach, 1993d)

How do they communicate with each other?

Altica subplicata finds and accepts host plants based on chemicals produced by the plant. Many similar beetle species also have their own chemicals that are used as defense against predators, and this is also likely true for A. subplicata. Willow leaf beetles communicate with other beetles through touch, during mating and when grouping together to feed, and can detect each other visually. They can also sense their environment visually, with smells and chemicals, and through touch. (Rowell-Rahier and Pasteels, 1986; Tahvanainen, et al., 1985)

What do they eat?

Altica subplicata is an herbivore that feeds on the leaves of willow plants. Along rivers over much of its habitat, this beetle feeds primarily on Salix interior, the sandbar willow, but it will also feed on Salix amygdaloides. On the shores of the Great Lakes it feeds on Salix cordata, the sand dune willow. Young larvae eat only on the underside of the leaves, while older larvae and adults eat the entire leaf, leaving only the veins. Larvae are far more likely to feed on young leaves. Adults will feed on older leaves, but are also more likely to eat younger leaves. (Bach and Carr, 1990; LeSage, 1995)

  • Plant Foods
  • leaves

What eats them and how do they avoid being eaten?

Carabid beetles of the genus Lebia are known to prey on Altica larvae, and are likely a predator of A. subplicata. It is possible that A. subplicata produces chemicals and uses them as defense, since related species are able to do this. The bright, metallic blue color of these beetles is called aposematic coloring. Predators know that bright colored beetles are often poisonous, so this bright blue coloring warns predators that A. subplicata might be poisonous too. A. subplicata also defends itself by grouping together in large numbers. A group of beetles or larvae appears much larger than a single beetle, looking more threatening to predators. (Bach, 1993b; Bach, 1993c; Bach, 1993d; DeSwarte and Balsbaugh, 1973; Pettis, 2005; Tahvanainen, et al., 1985)

  • These animal colors help protect them
  • aposematic

What roles do they have in the ecosystem?

Altica subplicata can affect what plant species are present on sand dunes in the Great Lakes region. In years where there are many willow leaf beetles, they can remove most of the leaves on willow plants. This damage to willow plants means that there may be less willow plants on the dunes. This causes empty space for other plant species to grow. A. subplicata may also compete with other similar beetle species for plants to eat, particularly the beetle Disonycha alternata on the sandbar willow. (Bach, 1990; DeSwarte and Balsbaugh, 1973; LeSage, 1995)

Species (or larger taxonomic groups) used as hosts by this species
  • Salix cordata
  • Salix interior
  • Salix amygdaloides

Do they cause problems?

There are no known negative affects of Altica subplicata on humans.

How do they interact with us?

There are no known positive effects of Altica subplicata on humans.

Are they endangered?

Altica subplicata is not an endangered species, but it is a major herbivore on sand dunes along the Great Lakes where several other threatened or endangered species occur.

Contributors

Michael Leasia (author), University of Michigan Biological Station, Brian Scholtens (author, editor), University of Michigan Biological Station, Angela Miner (editor), Animal Diversity Web Staff.

References

Bach, C. 1993. Effects of microclimate and plant characteristics on the distribution of a willow flea beetle, Altica subplicata. American Midland Naturalist, 130: 193-208.

Bach, C. 1993. Movement behavior of Altica subplicata (Coleoptera, Chrysomelidae) - effects of plant characteristics on patterns of adult movement. Journal of the Kansas Entomological Society, 66: 310-318.

Bach, C. 1993. Movement behavior of Altica subplicata (Coleoptera, Chrysomelidae) - larval orientation and movement. Journal of the Kansas Entomological Society, 66: 86-96.

Bach, C. 1994. Effects of a specialist herbivore (Altica subplicata) on Salix cordata and sand dune succession. Ecological Monographs, 64: 423-445.

Bach, C. 1993. Movement behavior of Altica subplicata (Coleoptera, Chrysomelidae) - effects of plant characteristics on patterns of adult movement. Journal of the Kansas Entomological Society, 66: 310-318.

Bach, C. 1990. Plant successional stage and insect herbivory: flea beetles on sand-dune willow. Ecology, 71: 598-609.

Bach, C., D. Carr. 1990. Aggregation behavior of a willow leaf beetle, Altica subplicata (Coleoptera, Chrysomelidae). Great Lakes Entomologist, 23: 65-76.

DeSwarte, D., E. Balsbaugh. 1973. Biologies of Altica subplicata and Disonycha alternata (Coleoptera: Chrysomelidae), two flea beetles that feed on sandbar willow. Annals of the Entomological Society of America, 66: 1349-1353.

Gannon, A., C. Bach, G. Walker. 1994. Feeding patterns and attachment ability of Altica subplicata (Coleoptera, Chrysomelidae) on sand-dune willow. Great Lakes Entomologist, 27: 87-101.

LeSage, L. 1995. Revision of the costate species of Altica Müller of North America north of Mexico (Coleoptera, Chrysomelidae). Canadian Entomologist, 127/3: 295-411.

Milanowski, D., C. Bach. 1994. Between-site variation in suitability of Salix cordata as a host for Altica subplicata (Coleoptera, Chrysomelidae). Great Lakes Entomologist, 26: 253-261.

Pettis, G. 2005. "Management of insect pests of crapemyrtle (Lagerstroemia spp) with special reference to the ecology and biology of Altica litigata Fall (Coleoptera: Chrysomelidae)" (On-line pdf). Athenaeum @ UGA. Accessed March 23, 2013 at http://athenaeum.libs.uga.edu/handle/10724/8204.

Rickelmann, K., C. Bach. 1986. Effects of soil-moisture on the pupation behavior of Altica subplicata (Coleoptera: Chysomelidae: Cassidinae). Journal of New York Entomological Society, 94: 98-114.

Rowell-Rahier, M., J. Pasteels. 1986. Economics of chemical defense in Chrysomelinae. Journal of Chemical Ecology, 12: 1189-1203.

Shen, C., C. Bach. 1997. Genetic variation in resistance and tolerance to insect herbivory in Salix cordata. Ecological Entomology, 22: 335-342.

Tahvanainen, J., R. Julkunen-Tiitto, J. Kettunen. 1985. Phenolic glycosides govern the food selection pattern of willow feeding leaf beetles. Oecologia, 67: 52-56.

 
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Leasia, M. and B. Scholtens 2013. "Altica subplicata" (On-line), Animal Diversity Web. Accessed December 22, 2014 at http://www.biokids.umich.edu/accounts/Altica_subplicata/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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