Silene latifolia temporal patterns of volatile induction and suppression after floral interaction by the nursery pollinator, Hadena bicruris (Lepidoptera: Noctuidae)

Authors: PIESIK, DARIUSZ - University Of Technology And Life Sciences; LYSZCZARZ, ALICIJA - University Of Technology And Life Sciences; Delaney, Kevin; BOCIANOWSKI, JAN - Poznan University Of Life Sciences; LIGOR, MAGDALENA - Nicolaus Copernicus University; BUSZEWSKI, BOGUSLAW - Nicolaus Copernicus University

Submitted to: Entomologica Fennica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/7/2014
Publication Date: 12/1/2014
Citation: Piesik, D., Lyszczarz, A., Delaney, K.J., Bocianowski, J.P., Ligor, M.N., Buszewski, B. 2014. Silene latifolia temporal patterns of volatile induction and suppression after floral interaction by the nursery pollinator, Hadena bicruris (Lepidoptera: Noctuidae). Entomologica Fennica. 25(4):199-219.

Interpretive Summary: Some plants interact with an insect species that affects the plant in more than one way. For example, some insects as adults may pollinate a plant while larvae feed on the plant. Thus, a host plant may have different volatile organic compound responses depending on whether interacting with a pollinating adult, an adult laying an egg on the plant, or a larva feeding on the plant. Studying white campion flowers and a nocturnal moth (pollinates flowers while larvae feed on seeds), we found that emission of several volatiles were progressively suppressed by 3 days after polliation (especially those compounds shown to be attractive to the moth). However, some volatiles were induced while others were suppressed after moth egg deposition onto flowers. Neighboring plants had essentially no alteration in volatile production when exposed to a pollinated plant. However, neighboring plants had brief induction or suppression of several volatiles when located 1m from a plant that had received moth eggs. These results provide further support that once a white campion plant has flowers pollinated this moth, volatile compound suppression may help reduce the likelihood of future interactions with the moth that could lead to egg deposition. Also, induction of some VOCs and suppression of other VOCs after moth egg deposition may be useful if natural enemies are attracted to the plant and then kill the eggs. Finally, neighboring plants may have unaltered volatile production because they receive less volatile stimulation from pollinated plants. In contrast, it may benefit neighboring white campion plants to prime or even induce defenses (e.g., volatiles) when a neighboring plant receives moth eggs, because there is an increased likelihood that a moth is nearby for egg deposition.

Technical Abstract: 1. Plant VOC emission can be induced or suppressed after herbivory, oviposition, or pollination, which may influence other trophic levels. Sometimes, a single insect species has multiple roles when interacting with a plant, e.g. as pollinator and herbivore. 2. Two experiments tested whether 14 selected constitutively emitted volatile organic compounds (VOCs) had quantitative temporal emission patterns for 3d following pollination or oviposition by Hadena bicruris Hufnagel 1766 (lychnis moth; Noctuidae) on Silene latifolia Poir. (white campion; Caryophyllaceae) female flowers. VOCs included ß-CAR = ß-caryopyllene, (E)-ß-FAR = (E)-ß–farnesene, 4-HEP = 4-heptanone; LA A - lilac aldehyde A, LA B = lilac aldehyde B, LA C = lilac aldehyde C, LA D = lilac aldehyde D, LIN = linalool, LOX = linalool oxide, ß-MYR = ß-myrcene, (Z)-OCI = (Z)-ß-ocimene, PHE – phenylacetaldehyde, ß-PIN = ß-pinene, and VER = veratrole. Follow-up experiments examined temporal VOC patterns with neighboring unpollinated or unoviposited plants. 3. Pollinated S. latifolia had slight suppression of two terpenes (ß-PIN, LIN) but progressively greater suppression of several aldehydes and two other terpenes (LA A - D, VER, and LOX). Some VOCs were induced (4-HEP, LIN, ß-MYR, and ß-PIN) or suppressed (LA B and VER) after H. bicruris oviposited onto S. latifolia, while for other VOCs the degree of induction ((Z)-OCI, ß-CAR, (E)-ß-FAR) or suppression (LA A & C) progressively decreased by 3d. Unpollinated S. latifolia neighboring a pollinated plant essentially had no VOC emission alteration. However, following 24h exposure to a neighboring oviposited conspecific at 1m, unoviposited S. latifolia had VOC induction across all 3d (ß-PIN, ß-MYR), or brief induction ((E)-ß-FAR, ß-CAR, and LIN) or suppression (LA A, VER, and LOX). 4. Pollination of S. latifolia by H. bicruris mostly suppressed VOC production, and neighboring plant VOC production was essentially unaltered. Floral VOC reduction after pollination may help to avoid oviposition. Neighboring plant VOC induction was weaker than but paralleled oviposited S. latifolia VOC responses. These S. latifolia VOC changes after H. bicruris oviposition may help attract natural enemies to eggs, while neighboring plants can prepare when an herbivore is nearby.