Data from: Non-glandular trichomes chemically and physically damage herbivores
More than impede insect movement, recent studies have shown that non-glandular trichomes directly defend plants by suppressing the growth, survival, and reproduction of small herbivores. Tobacco hornworm larvae (Manduca sexta) consuming diets containing trichomes show signs of greater metabolic activity, which may include the up regulation of upregulating tissue repair and immune response genes to repair damage from consuming trichomes. What is not yet understood is whether trichomes affect larvae through nutritional, chemical, or physical mechanisms. To answer this question, this study established a series of treatments that compared intact and manipulated trichomes added to artificial diet to assess the chemical and physical features of stellate, non-glandular trichomes of horsenettle (Solanum carolinense). Grinding disrupted the physical shape of trichomes while leaving the chemical composition intact. Cooking disrupted both the trichome shape and chemistry. A final experimental treatment incorporated indigestible, rounded carbon pellets to decrease the nutritional density of the diet, to simulate undigested trichomes, without the consequences of a sharp shape or toxic chemicals. Tobacco hornworm larvae that fed on intact trichomes consumed the least diet, gained the least mass, and were the most metabolically active. Larvae that fed on diet containing ground trichomes did not show quite the same reductions in diet consumption and mass gain or increase in metabolic activity as compared to larvae that fed on diet with intact trichomes, which indicated that manipulating the physical shape of trichomes only partially reversed the harmful effects of trichomes. Larvae that fed on diet containing cooked trichomes or carbon pellets had similar 66consumption and metabolic activity to larvae that fed on control diets without any additives, which indicated that manipulating both trichome physical shape and chemistry reversed the harmful effects of intact trichomes and that trichomes did not reduce the nutritional density of diets. Building on these results, the physical impacts of trichomes following consumption were further assessed by tracking the location of diet within larvae using a fluorescent powder. Fluorescent powder was found outside the gut lumen within the hemolymph of larvae reared on diets containing trichomes, but not in the larvae fed on diets without trichomes. This indicated that trichomes puncture the midgut epithelium of larvae allow the contents of the gut to leak into the surrounding hemocoel. Overall, this study found that, following consumption, non-glandular trichomes inhibit larval feeding and growth through chemical and physical mechanisms that disrupt the integrity of the larval gut.
|Data from: Non-glandular trichomes chemically and physically damage herbivores
|CC BY 4.0 (Attribution)
|February 16, 2021
|February 15, 2021
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