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Energy Flow and Grazing Behavior of Conocephaline Grasshoppers in a Juncus Roemerianus Marsh
Author(s) -
Parson Keith A.,
De La Cruz Armando A.
Publication year - 1980
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1936822
Subject(s) - juncus , biology , grazing , botany , trophic level , decomposer , spartina , herbivore , ecology , marsh , wetland , ecosystem
At least three species of conocephaline grasshoppers (Tettigoniidae) from the major grazing herbivores on the leaves of the marsh black needlerush Juncus roemerianus Scheele. They ingested 105 kJ/m 2 of the 31.62 MJ/m 2 net annual aboveground production of Juncus. Assimilation of ingested Juncus tissue was 60.7 kJ°m — 2 °yr — 1 and production of new tissue by the grasshoppers was 9.6 kJ°m — 2 °yr — 1 , which represents 0.03% of the net annual primary production. A secondary effect of grazing was manifested by the premature death of portions of the Juncus leaf distal to the grazed area. Subsequent mechanical breakage resulted in early deposition of broken—off leaf tips into the detrital mat on the marsh. This represented a maximum input into the decomposer trophic level of 246 kJ°m — 2°yr — 1 prior to the death and deposition of the entire Juncus leaf. The addition of Juncus to the diet of the conocephaline post—nymphal and adult stages is discussed in the light of the hypothesis that C 4 plants are nutritionally inferior to C 2 plants, based on comparisons of amino acid concentrations within different parts of the Juncus leaf and in comparison with Spartina cynosuroides.