Journal of Chemical Ecology

Vander Meer, Robert K.; Porter, Sanford D.; Cardoza, Yasmin J.

doi: 10.1007/s10886-026-01710-wpmid: 42126630

We previously determined that electrically stimulated fire ants release exocrine gland products, e.g., venom, recruitment and alarm pheromones. We hypothesized that exocrine gland emissions from electrically stimulated fire ant workers might attract phorid fly parasitoids of fire ants. Bioassays demonstrated that electrically stimulated worker ants did attract phorid fly parasitoids in the field. Phorid fly (Pseudacteon tricuspis) mass rearing boxes were then used for lab bioassays to determine the glandular source and active components from electrically stimulated fire ants that elicited phorid fly attraction. The crude extract of fire ant poison sacs showed a significant increase in attacking phorid flies at the 10 min evaluation time, whereas purified venom alkaloids had no effect on phorid flies. Dufour’s glands (the source of recruitment pheromones) elicited no fly activation/attraction. However, mandibular gland extracts, the source of alarm pheromones, were found to activate and attract phorid flies. Moreover, a previously identified pyrazine alarm pheromone from mandibular glands was found to be the active component. This was confirmed by specific alarm pheromone bioassays showing the expected ephemeral characteristic of the attraction and by directly using synthetic fire ant alarm pheromone. Use of the fire ant alarm pheromone may aid in detecting the presence of phorid flies in the field and in increasing attack/parasitism rates during mass production.

Schlager, Martin; Manhalter, Stephan; Wechselberger, Katharina; Kárpáti, Zsolt; Dötterl, Stefan

doi: 10.1007/s10886-026-01712-8pmid: 42018093

The western corn rootworm (WCR, Diabrotica virgifera virgifera) is one of the most serious pests in maize. In some parts of Europe, maize is frequently cultivated adjacent to the Styrian oil pumpkin (Cucurbita pepo pepo var. styriaca). Adult beetles are strongly attracted to the flowers of this cucurbit, likely due to their strong scent, and lay some of their eggs in the soil of the pumpkin crop. This makes crop rotation, an otherwise effective pest control strategy, less effective. Here, we used gas chromatography coupled to electroantennographic detection (GC-EAD) and field biotests to identify floral scent compounds of the oil pumpkin that elicit physiological and behavioural responses in WCR, respectively. We identified 18 non-sex specific EAD-active compounds for WCR. In field tests, 1,4-dimethoxybenzene, the main compound in pumpkin floral scent, was not attractive to WCR, whereas (E)-p-methoxycinnamaldehyde, a minor compound, was as attractive as the complete pumpkin mixture. This research provides the basis for developing an attract and kill system, to prevent, or at least mitigate, the substantial yield losses caused by WCR.

Ranger, Christopher M.; Baniszewski, Julie A.; Patwa, Nisha; Wei, Hsin-Ho; Pachhain, Sudhan; Raubenolt, Jessi A.; Altland, Madeline; Cambronero-Heinrichs, Juan Carlos; Phuntumart, Vipaporn; Reding, Michael E.; Rassati, Davide; Keesey, Ian W.; Biedermann, Peter H. W.

doi: 10.1007/s10886-026-01725-3pmid: 42216980

Wood-boring ambrosia beetles and their offspring obligately depend on cultivated fungi that they maintain within host trees. Stressed trees produce at least two potent antimicrobials, ethanol and acetic acid, which typically suppress the growth of most fungi. Ethanol facilitates the growth of ambrosia beetles’ fungal mutualists and thus aids in host colonization; however, acetic acid’s effects are unknown. Here, we evaluated the effects of acetic acid on tunneling and offspring production by two exotic ambrosia beetle species, Xylosandrus germanus and Anisandrus maiche. Cut wood stems (i.e., bolts) were infused with water alone, 5% ethanol, or mixtures of 5% ethanol with acetic acid at various dilutions. Infestations by X. germanus and A. maiche resulted in more frass, larvae, pupae, and adults in the combined 5% ethanol-acetic acid treatment, than in the 5% ethanol alone or water control treatments. X-ray micro-computed tomography revealed that bolts infused with this 5% ethanol-acetic acid mixture had larger insect gallery volumes than those with only 5% ethanol, which in turn were larger than the water control. A positive relationship was found between frass ejected by each beetle and gallery volume across all experiments. This study demonstrates that acetic acid and ethanol synergistically increase offspring production while facilitating gallery expansion by the larvae. Understanding how ambrosia beetles utilize stress-induced compounds within host trees to benefit their fungiculture could lead to novel management strategies for these invasive insects.

Uenoyama, Reiko; Miyazaki, Tamako; Ooka, Sae; Nishikawa, Toshio; Miyazaki, Masao

doi: 10.1007/s10886-026-01717-3pmid: 42120796

Chemical cues that appear potent in controlled laboratory bioassays do not necessarily function as effective behavioural cues under natural conditions, where animals can freely approach or ignore stimuli. How chemical detectability translates into voluntary behavioural engagement, therefore, remains an important unresolved question. Plant-derived semiochemicals provide a tractable system for examining this issue because the same compounds can be presented either as intact natural sources or as purified chemicals. Domestic cats (Felis silvestris catus) show a characteristic self-anointing response to iridoid-producing plants, including catnip (Nepeta cataria) and silver vine (Actinidia polygama), both widely regarded as cat-attractants. Here, we tested whether these plants differ in their ability to induce voluntary engagement under free-choice conditions. Free-roaming cats rarely showed self-anointing behaviour (face-rubbing and rolling) toward intact catnip plants, but consistently engaged with silver vine. The same bias toward silver vine was observed in captive cats presented simultaneously with plant extracts. Chemical analyses confirmed that catnip contained abundant bioactive nepetalactone, indicating that weak responsiveness was not explained by a lack of bioactive compounds. These findings demonstrate that chemical abundance and laboratory bioactivity do not necessarily predict behavioural reliability under natural encounter conditions. Instead, whether a cue consistently elicits voluntary engagement may determine its ecological effectiveness as a behavioural cue.

Giguère, Thomas; El Marahi, Célia; Lunel, Christophe; Bussy, Mathieu; Andruszkow, Léo; Paty, Chrystelle; Cortesero, Anne Marie; Hervé, Maxime R.

doi: 10.1007/s10886-026-01724-4pmid: N/A

A key postulate in chemical ecology is that specialist herbivore insects have evolved abilities to tolerate chemical defenses specific to their host plants. Nevertheless, past studies have shown that this assumption does not always hold true. Identifying the compounds responsible for this occasional paradigm shift is essential for improving our understanding of plant-insect interactions, and for the development of new control strategies against specialized insect pests. In this study, we examined the relationship between the chemistry of Sinapis alba L. (Brassicales: Brassicaceae) and adult feeding in Psylliodes chrysocephala L. (Coleoptera: Chrysomelidae), i.e., a Brassicaceae specialist and major oilseed rape pest. A variation in the ability of different S. alba cultivars to resist feeding by this insect pest was exploited to identify deterrent compounds. A comparative bioassay-guided fractionation approach led to the hypothesis that sinalbin, a glucosinolate specific to S. alba and few other brassicaceous species, might deter feeding of P. chrysocephala adults. Pure sinalbin was tested at various concentrations, confirming its deterrent effect at a concentration naturally found in leaves of two-week-old plants, i.e., 15 nmol.mg− 1 FW. Such results provide new insights into host selection mechanisms of Brassicaceae specialists, i.e., that avoidance of intact glucosinolates may also contribute to preference. From an applied perspective, the identification of sinalbin as a biomarker of resistance in S. alba has the potential to guide future efforts into the development of new management strategies for oilseed rape pests such as P. chrysocephala.

Aditi, BV; Desai, Chena; Sreenivas, Darshan; Ramakrishnan, Uma; Olsson, Shannon

doi: 10.1007/s10886-026-01722-6pmid: 42213247

Chemical cues play an important role in mammalian communication, often reflecting an individual’s physiological state. Non-invasive sampling of such informative cues holds great potential for wildlife monitoring. Endangered apex predators such as big cats are elusive and challenging to monitor. While existing monitoring techniques estimate numbers or densities, they often fail to provide crucial demographic and physiological information. We adapted a headspace solid-phase field sampling technique adapted for sampling volatiles from urine and faeces of captive Bengal tigers and Indian leopards of known age and sex, and from urine of identified wild Bengal tigers of known age, sex, and reproductive status. Volatiles extracted from these samples were analysed using Thermal Desorption- Gas Chromatography-Mass Spectrometry. The random forest algorithm was used to identify compounds that might be cues for species, age, sex, and reproductive state. Species classification accuracy was consistently high with both urine (0.79 + 0.009) and scat (0.75 + 0.029) volatiles. Classification accuracy of urine volatiles was high for females and young individuals in leopards and tigers, but lower for males and old individuals. Scat volatiles performed better across groups. We also identified putative chemical markers for epilepsy and reproductive state in tigers. This study presents the first chemical characterization of tiger and leopard scats and the first sampling of tiger odours from the wild. Our simple and cost-effective method of sampling tiger and leopard odours offers a novel method of chemical fingerprinting to monitor populations in situ. Importantly, this sampling method and analytical pipeline is broadly applicable to other mammalian species for conservation and ecological studies.

Baleba, Steve B. S.

doi: 10.1007/s10886-026-01705-7pmid: 42018030

Filth flies are groups of dipteran species closely associated with human and animal faeces, food waste, or carrion. They include species such as the house fly (Musca domestica), face fly (Musca autumnalis), bazaar fly (Musca sorbens), false stable flies (Muscina stabulans, Muscina levida), lesser house fly (Fannia canicularis), stable flies (Stomoxys spp.), horn fly (Haematobia irritans), neglected blood feeder fly (Musca crassirostris), oriental latrine fly (Chrysomya megacephala), green bottle fly (Lucilia sericata), Australian sheep blowfly (Lucilia cuprina) and blue bottle fly (Calliphora vicina). Thriving on decomposing organic waste, sewage, animal faeces, and carrion, these flies act as mechanical vectors of viruses, bacteria, protozoa, and helminths. They also cause direct harm through annoyance, stress, skin lesions, blood loss, and immunosuppression. In humans, contact with contaminated items, body parts, or food results in diseases such as trachoma, chlamydia, cholera, and gastrointestinal infections. In livestock, infestations lead to reduced weight gain and milk yield, causing economic losses exceeding USD 2 billion annually. Like all insects, filth flies rely heavily on olfaction to locate food, mates, oviposition sites, shelters, and to avoid danger. Identifying the odour cues that guide these behaviours offers promising opportunities for control, particularly when integrated into trapping or repellent systems. This review summarises current knowledge on filth fly management using odour cues. It explains the nature of these cues and their detection mechanisms in insects, discusses studies applying them for monitoring, attraction, repellency, or mass trapping, and highlights key considerations for developing effective odour-based control strategies. The review provides a useful reference for veterinarians, entomologists, chemical ecologists, industry, and funding agencies seeking sustainable alternatives for managing filth flies.

Schäfer, Marcel; Zohmann-Neuberger, Margit; Forbey, Jennifer Sorensen; Tintner-Olifiers, Johannes; Hromatka, Angelika; Inselsbacher, Erich; Dépré, Chloé; Nielsen, Ólafur Karl; Nopp-Mayr, Ursula

doi: 10.1007/s10886-026-01716-4pmid: 42108314

Availability and quality of vegetation are critical factors influencing herbivore nutrition and population dynamics. Fourier-transform infrared spectroscopy (FTIR) offers a promising approach to analyze herbivore diets using spectral properties of phytochemicals to identify plant items. We evaluated the potential of FTIR to identify plant taxa and parts consumed by an herbivore species. Crop contents from 236 rock ptarmigan (Lagopus mutaMontin) individuals from Iceland, collected over nine years, were separated into pure fractions of plant taxa and parts (e.g., berries, leaves) and analyzed using FTIR in the mid-IR region (4000 –400 cm⁻¹). We classified plant taxa and parts with PCA and Random Forests (RF) based on spectral signals. FTIR revealed distinct chemical fingerprints for plant taxa and parts, consistent with previously established variation in lipids, proteins, carbohydrates, and chemical defenses. RF yielded high classification accuracy for plant parts (96.7%) and moderate accuracy for taxa (85.5%), confirming the method’s reliability. FTIR overcomes limitations of traditional genetic analyses by identifying plant parts with varying nutritional quality within species. FTIR provided insights into biochemical properties of plant items but could not distinguish chemically similar items. Future research should expand spectral reference libraries combining FTIR with quantification of phytochemicals and DNA metabarcoding.

Huh, Min-Jung; Roh, Gwang-Hyun; Park, Kye-Chung; Park, Il-Kwon

doi: 10.1007/s10886-026-01714-6pmid: 41999533

Monochamus alternatus Hope and Monochamus saltuarius Gebler (Coleoptera: Cerambycidae) are insect vectors of the pine wood nematode (PWN) on the Korean peninsula. Although they share an identical aggregation-sex pheromone, the two species exhibit different synergistic responses to host volatiles and other semiochemicals. In this study, we examined the electrophysiological responses of olfactory sensilla in both species to 22 semiochemicals, including pheromone, bark beetle pheromones, and host volatiles. Single-sensillum recordings (SSR) identified two distinct groups of basiconic-type olfactory sensilla, each associated with different functional groups. Sensilla basiconica A (SBaA) contained specialized olfactory sensory neurons (OSNs) that could be functionally distinguished into non-responsive, specialist like pheromone specialist, and generalist OSNs. In contrast, OSNs in sensilla basiconica B (SBaB) did not show clear functional classification into specific odor groups. Therefore, they were classified based on the number of compounds eliciting responses, as non-responsive neurons, specialists, and generalists. Notably, enantiomer-specific differences were observed among generalist OSNs. Most OSNs responded to both (+)- and (−)-α-pinene enantiomers, whereas a significantly higher proportion of OSNs showed exclusive responses to (−)-limonene compared to (+)-limonene. These results provide new insight into the olfactory mechanisms that underlie species-specific behavioral responses to semiochemicals in these economically important beetle vectors.