Altica subplicata

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Geographic Range

Altica subplicata, 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 highest concentration of this species is along the Mississippi River and the Great Lakes, extending west to the Rocky Mountains. (LeSage, 1995)

Habitat

Altica subplicata thrives in sand dune habitats along the Great Lakes and on sand bars in rivers. The density of beetle populations decreases significantly with increasing distance from shore on the Great Lakes, and beetles are not found on plants further than 16 meters from the shore. Willow leaf beetles are more abundant on young dunes than intermediate or old dunes. (Bach, 1993a; DeSwarte and Balsbaugh, 1973)

Physical Description

Altica subplicata has an oblong, 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. Larvae of A. subplicata are deeply pigmented. Females of this species tend to be larger than males. The elytra are low and weakly developed. The frontal tubercles are flat, and very finely alataceous and well defined posteriorly by post ocular sulci. It has a well defined coronal suture between the eyes, though the eyes are not prominent. The inner pair of setae are distinctly shorter than others. Willow leaf beetles have a quadrate pronotum with a deep transverse groove throughout. A. subplicata is distinguished from other low costate species as having a dull elytron surface with a deeper microsculpture. (LeSage, 1995)

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

Development

Eggs of A. subplicata are laid in the spring. Larvae hatch after about 7 days, and go through 3 larval 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 emerge and feed through the rest of the summer. During the first cold nights of autumn, adults leave the host plant and overwinter in leaf litter, under stones, logs, and bark. Adults emerge in the spring, find mates, and then oviposit on host leaves. In total, one generation takes about 34 days to complete, with the resulting adults living for an extended period of time after emergence. (DeSwarte and Balsbaugh, 1973; LeSage, 1995; Rickelmann and Bach, 1986)

Reproduction

Adults become sexually mature during winter. After overwintering, the willow leaf beetles appear on plants in early spring. The preoviposition period lasts 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. Multiple matings are very common. (LeSage, 1995)

Adults of Altica subplicata emerge from diapause in the spring and enter a prereproductive period of just over 1 week. They then start mating and ovipositing. Females deposit eggs horizontally in small clusters on the undersurface 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. The male to female ratio in an egg mass is 1:1. In the southern part of the United States, A. subplicata has 2 or more generations each summer. In northern states and Canada, A. subplicata has only one generation during the year. (DeSwarte and Balsbaugh, 1973; LeSage, 1995)

  • Breeding interval
    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

There is no parental involvement in development other than provisioning of eggs.

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

Lifespan/Longevity

A typical generation from egg to adult takes about 34 days. Adults live for an extended time after emergence. The final generation of adults enters diapause through the winter and starts mating and egg-laying again in the spring. (DeSwarte and Balsbaugh, 1973; LeSage, 1995)

  • Typical lifespan
    Status: wild
    2 to 12 months

Behavior

Larvae of Altica subplicata aggregate in large groups on willow tree hosts to feed, but regularly move from one plant to another. Adults also aggregate on hosts. They tend to aggregate more frequently on host plants that occur in high humidity habitats and have taller stems. On dune habitats in the Great Lakes, they concentrate on the youngest dunes near the shore, and avoid host plants on older, heavily vegetated dunes. It has been shown in other willow-feeding Chrysomelinae that phenolic glycoside composition can have a major effect on host choice, and this is likely the case with this species also. Both males and females can fly, though they do not fly long distances as they keep close to shore. Adults become more active and airborne when looking for mates. A. subplicata is most active during the day. (Bach, 1993a; Bach, 1993b; Bach, 1993c; Gannon, et al., 1994; Bach, 1993a; Bach, 1993b; Bach, 1993c; Gannon, et al., 1994; Bach and Carr, 1990; Bach, 1993a; Bach, 1993b; Bach, 1993c; Gannon, et al., 1994; Tahvanainen, et al., 1985)

Home Range

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

Communication and Perception

Altica subplicata is generally known to find and accept host plants based on phenolic glycoside content. Many similar species also sequester compounds that are used as defense. This is well documented in some Chrysomelinae, and it is suspected that A. subplicata sequesters defense compounds as well. Willow leaf beetles communicate with other beetles through touch, during mating and aggregation, 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)

Food Habits

Altica subplicata is a specialist herbivore on willows. Along rivers over much of the range, 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 later instars and adults eat the entire leaf, leaving only the veins. Larvae are far more likely to feed on young leaves with a high density of trichomes. Adults will feed on older leaves, but are also more likely to eat younger leaves. (Bach and Carr, 1990; LeSage, 1995)

  • Plant Foods
  • leaves

Predation

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 sequesters phenolic glycosides and uses these as defense, as is known for some willow-feeding Chrysomelinae. The bright, metallic blue coloration (likely aposematic) and aggregation behavior also suggest this could be true. The aggregation behavior itself also functions as a defensive mechanism, allowing both the larvae and the adults to appear larger and more intimidating. (Bach, 1993b; Bach, 1993c; Bach, 1993d; DeSwarte and Balsbaugh, 1973; Pettis, 2005; Tahvanainen, et al., 1985)

Ecosystem Roles

Bach (1990) documented that Altica subplicata affects plant species composition and potentially succession on sand dunes in the Great Lakes region. In outbreak years, this species severely defoliates its host plant, and likely modifies its reproductive capabilities, causing non-host plants to be more abundant in areas with high beetle density. A. subplicata may be a competitor with other willow-feeding beetles, particularly Disonycha alternata on Salix interior. (Bach, 1990; DeSwarte and Balsbaugh, 1973; LeSage, 1995)

Species Used as Host
  • Salix cordata
  • Salix interior
  • Salix amygdaloides

Economic Importance for Humans: Positive

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

Economic Importance for Humans: Negative

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

Conservation Status

This species is not a conservation concern, but it is a major herbivore on dunes habitats 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.

Glossary

Nearctic

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.

World Map

aposematic

having coloration that serves a protective function for the animal, usually used to refer to animals with colors that warn predators of their toxicity. For example: animals with bright red or yellow coloration are often toxic or distasteful.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

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. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

diapause

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.

diurnal
  1. active during the day, 2. lasting for one day.
ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

fertilization

union of egg and spermatozoan

folivore

an animal that mainly eats leaves.

herbivore

An animal that eats mainly plants or parts of plants.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

hibernation

the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

internal fertilization

fertilization takes place within the female's body

metamorphosis

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.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

poisonous

an animal which has a substance capable of killing, injuring, or impairing other animals through its chemical action (for example, the skin of poison dart frogs).

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

seasonal breeding

breeding is confined to a particular season

semelparous

offspring are all produced in a single group (litter, clutch, etc.), after which the parent usually dies. Semelparous organisms often only live through a single season/year (or other periodic change in conditions) but may live for many seasons. In both cases reproduction occurs as a single investment of energy in offspring, with no future chance for investment in reproduction.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

temperate

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).

terrestrial

Living on the ground.

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

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.