Florivory can facilitate rain-assisted autogamy in a deceptive tropical orchid.

Florivores and rainfall generally have negative impacts on plant fecundity. However, in some cases, they can mediate fruit set. Some plants face severe pollen-limited fecundity and any additional fruit set, even if from self-pollination, can be advantageous. This is the case in some tropical deceptive orchids, such as the threatened Cyrtopodium hatschbachii. Here we test the hypothesis that florivory of the anther cap would facilitate rain-assisted autogamy in this species. In the field, we followed flowers in which the anther cap was removed by the orthopteran Stenopola sp. and found cases where pollinia self-deposited after rainfall and in one case this resulted in swelling of the column typical of fruit development. This event comprised 33% of all fruit set in the population in 2019. We then experimentally varied anther cap removal and rainfall in a factorial design and found increased fruit set in the group with cap removal (simulated florivory) followed by rain. The water absorption by pollinia makes them heavier, causing the stipe to bend. The droplet of water on the stigma then shrinks and pulls the pollinia back onto the stigma, causing self-pollination. Seeds from self-pollination have considerable viability and may allow population persistence, given that bee-mediated cross-pollination is uncertain and even absent in some years. Our study provides a unique example of how two unrelated factors (i.e., florivory and rain) that are detrimental alone may together promote fruit set.

Correction to: How the activity of natural enemies changes the structure and metabolism of the nutritive tissue in galls? Evidence from the Palaeomystella oligophaga (Lepidoptera) -Macairea radula (Metastomataceae) system.

The original version of this article unfortunately contains an error. The correct caption of Figures 2 and 3 are shown in this paper.

How the activity of natural enemies changes the structure and metabolism of the nutritive tissue in galls? Evidence from the Palaeomystella oligophaga (Lepidoptera) -Macairea radula (Metastomataceae) system.

Insect-induced galls usually develop nutritional cells, which they induce and consume directly, and any metabolic modification of those cells may reflect changes of the insect's own metabolism. The system Palaeomystella oligophaga (Lepidoptera)-Macairea radula (Melastomataceae) presents a series of natural enemies, including parasitoids and cecidophages that can function as a natural experiment, respectively removing the specific galling feeding stimulus and providing a nonspecific one. Considering that the process of induction and maintenance of gall tissues strictly depends on the constant specific stimulus of galling, question I:What kind of metabolic changes these different groups of natural enemies can promote in chemical and structural composition of these galls? II: How the specialized tissues are metabolically dependent on the constant specific stimulus of galling in latter stages of gall development? Galls without natural enemies, with parasitoids or cecidophages in larvae or pupae stages were analyzed through histochemistry and cytological profiles and all compared to galls in natural senescence state. The analysis revealed the accumulation of proteins and lipids in typical nutritive tissue and starch in the storage tissue, as well a high integrity of cellular organelles and membrane systems on galls with gallings in the larval stage. Both parasitoids and cecidophages stop galling feeding activities, which resulted in the paralysis of the stimulus that maintain the metabolism of gall tissues, leading to generalized collapse. We demonstrate that the development and metabolic maintenance of a typical nutritive tissue in these galls are completely dependent on constant larval stimulus.