Elasmostethus

Fieber, 1860

Birch shieldbug

Species Guides

3

Elasmostethus is a of shield bugs in the Acanthosomatidae, comprising approximately 15 described distributed across the Holarctic region. The genus is notable for exhibiting asocial —specifically, the absence of maternal care of —contrasting with subsocial species found elsewhere in the family. Species within this genus show significant interspecific variation in traits including egg size, developmental periods, and female body size, though clutch size remains relatively consistent across species.

Elasmostethus interstinctus by (c) Andrew Meeds, some rights reserved (CC BY), uploaded by Andrew Meeds. Used under a CC-BY license.Elasmostethus interstinctus by (c) Tina Ellegaard Poulsen, some rights reserved (CC BY), uploaded by Tina Ellegaard Poulsen. Used under a CC-BY license.Elasmostethus by (c) Katja Schulz, some rights reserved (CC BY). Used under a CC-BY license.

Pronunciation

How to pronounce Elasmostethus: //ɨˌlæzməˈstiːθəs//

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Distribution

Holarctic distribution with records from Europe (Denmark, Norway, Sweden), North America (Vermont, United States), and Japan. Individual have more restricted ranges; for example, E. interstinctus (birch shieldbug) is widespread in Europe.

Life Cycle

occurs before . In E. interstinctus, nymphs from later-laid have reduced time to gather resources before overwintering. Egg developmental periods vary among . No maternal care of eggs is exhibited by any species in the .

Behavior

Asocial with no maternal care of , distinguishing the from subsocial Acanthosomatidae that guard eggs. Females allocate reproductive resources differently across the reproductive period: relatively more to offspring number early in life, more to offspring quality (larger eggs) later in life.

More Details

Reproductive allocation patterns

In E. interstinctus, size increases over the reproductive period—eggs are smaller at the beginning and middle than at the end. Clutch mass and egg number per clutch decrease in laying sequence, with first clutches substantially larger than subsequent ones. Lifetime correlates positively with female size, though egg size does not vary with female size. Offspring survival to adulthood increases with egg weight.

Interspecific life history variation

Among six Japanese studied (E. amabilis, E. brevis, E. humeralis, E. interstinctus, E. kerzhneri, and E. nubilus), significant differences were found in size/weight, egg developmental periods, and female size. Only clutch size showed no significant interspecific variation.

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