The occurrence and distribution of Tuckerella japonica (Acari: Tuckerellidae) on tea bushes, Camellia sinensis and C. assamica, in Alabama, Georgia and South Carolina, USA.

Adults, immatures and eggs of Tuckerella japonica (Ehara) were collected from unknown clones or varieties of Camellia sinensis (L.) O. Kuntze tea bushes in the Clemson University Farm, Coastal Research and Education Center, Charleston, South Carolina; from Assam hybrids in The Caw Caw Nature Preserve in Ravenel, SC; from C. sinensis and C. assamica (Masters) in the Charleston Tea Plantation on Wadmalaw Island, SC; C. sinensis in the Fairhope Tea Plantation in Fairhope, Alabama; and from C. sinensis 'Rosea' and a C. sinensis and C. assamica hybrid in Savannah and Ellabell, Georgia, between 1994 and 2015. This mite was consistently collected from 1-, 2- and 3+-year-old wood of tea plants with significantly greater numbers collected from 2-year-old wood. All stages of the mite were found within longitudinally split areas of the wood where underlying green bark tissues were exposed. As 1-year-old wood matured, there was increased splitting of the bark with increased mite presence. Mature green fruit (= developing seed pods) of tea were also frequented by T. japonica between June-July and October and their numbers were no greater than those on 1- or 3+-year wood. When the fruit were small (March-May) or as they hardened in late fall, they were not suitable feeding sites for this mite. Very few T. japonica were collected from 50 mature, inner or outer leaf samples with none usually found. Tuckerella japonica has multiple, overlapping generations and occurs on tea throughout the year in Alabama, Georgia and South Carolina, USA.

Climatic gradients of arms race coevolution.

In nature, spatiotemporally dynamic coevolutionary processes play major roles in the foundation and maintenance of biodiversity. Here, we examined the arms race coevolution involving a seed-eating weevil with a long snout and its camellia plant host with a thick fruit coat (pericarp) throughout the marked climatic gradient observed across the Japanese islands. Results demonstrated that female weevils, which bored holes through camellia pericarps to lay eggs into seeds, had evolved much longer snouts than males, especially in areas in which Japanese camellia pericarps were very thick. The thickness of the plant pericarp was heritable, and the camellia plant evolved a significantly thicker pericarp on islands with the weevil than on islands without it. Across populations with weevils, resource allocation to plant defense increased with increasing annual mean temperature or annual precipitation, thereby geographically differentiating the evolutionary and ecological interactions between the two species. Given that the coevolutionary relationship exhibited appreciable variation across a relatively small range of annual mean temperatures, ongoing global climatic change can dramatically alter the coevolutionary process, thereby changing the ecological interaction between these species.