- Author: Saoimanu Sope
Sugar-feeding ants protect pests that infect trees and damage the fruit they bear. Insecticides are often a go-to solution, but may kill beneficial insects in the process, too. Thankfully, Mark Hoddle, University of California Cooperative Extension entomologist and biological control specialist at UC Riverside, together with UCR colleagues in chemical engineering, developed a biodegradable hydrogel baiting system that targets ant populations, which protect sap-sucking pests from their natural enemies. Control of ants allows beneficial parasitoids and predators to greatly reduce pest populations.
Deciding to expand Hoddle's research was a “no-brainer” according to David Haviland, UC Cooperative Extension farm advisor in Kern County.
Haviland is investigating active ingredients that can be effectively used in hydrogel baiting systems. His research builds on Hoddle's use of alginate gels, also known as water beads, soaked in sugar water to control Argentine ants.
“What we're doing in California can benefit places like Florida, Texas, Mexico and beyond,” Haviland said.
The Hoddle lab conducted two years of orchard research showing that when ants are controlled, the amount of citrus flush infested with Asian citrus psyllid (ACP), a mottled brown insect that vectors the pathogen causing citrus greening, decreases by 75%. Citrus flush refers to newly developed leaves.
“But benefits are not restricted to just ACP with Argentine ant control, as natural enemies destroy colonies of other sap-sucking pests too,” said Hoddle. “For example, citrus mealybug infestations on leaves were completely eliminated by natural enemies, 100% control, while densities of fruit infested by mealybugs were reduced by 50%.”
The Hoddle lab's success inspired Haviland to consider how this approach will fare in different regions of the state where there are different crops, different pests and different ant species.
Haviland has worked for many years on solid baits that are effective and affordable for ants that feed primarily on protein, like fire ants in almonds, but successful control measures for sugar-feeding ants that drink their food have been elusive.
“Therefore, we're using hydrogels to essentially turn a liquid bait into a solid, making it effective and commercially adoptable,” Haviland said. He and his team are assessing whether active ingredients that undoubtedly work against ants, like thiamethoxam, maintain their effects in a hydrogel system.
Unlike Hoddle's biodegradable alginate gels, Haviland is relying on acrylamide gels that are similar to the absorbing material you would find in a diaper. These gels are not organic, but are currently accessible on a commercial scale, and have been shown to be effective in wine grapes on the North Coast by a Cooperative Extension advisor in Napa County, Monica Cooper. Haviland's current research efforts are focused on citrus, table grapes and wine grapes in the San Joaquin Valley, and on lemons on the coast.
The primary challenge now is navigating pesticide regulations and registration.
“This is cutting-edge research,” Haviland said, and manufacturer labels for the products being used need to be updated to include hydrogels as an approved use. This process takes time. Additionally, adding new product uses needs to make economic sense for the manufacturer.
Hoddle and Haviland's research can provide data for adding these methods to the product labels.
“If we can show that this tech works against lots of pests, lots of ant species, in lots of different crops across California, hopefully we'll achieve a critical mass of benefits that motivates product manufacturers to make modifications to their labels,” said Haviland.
Haviland is hopeful about the process, and said he believes that UC ANR is in a prime position to lead innovation for an issue that requires collaboration among specialists, advisors and the industry.
- Author: Ben Faber
Argentine Ant is the great protector of many pests found on plants. Without the Argentine, many pests would not be so much of a problem. In many crops, like cherimoya and passionfruit, mealy bug can become so severe that fruit will stop growing and fall off the tree. Controlling Argentine, makes it possible for predators and parasites to do their thing in bringing them under control. Watch these two videos to see how hoverflies (syrphids) can help biocontrol and how Argentine Ant control can help that biocontrol
Citrus Psyllids Bribe Ants With Strings Of Candy Poop | Deep Look - YouTube
How Hoverflies Spawn Maggots that Sweeten Your Oranges | Deep Look - YouTube
Cherimoya fruit and stems covered with mealy bug.
- Author: Ben Faber
It might seem like common sense that a starving animal is more likely to take dangerous risks to obtain food than one with a full belly. But new research from UCLA shows that groups of Argentine ants, who forage boldly when they're well fed, exercise far more caution when they've been deprived of carbohydrates and the risks from competitors are high.
This counterintuitive foraging strategy might contribute to the success of these insects, known as Linepithema humile, an invasive species that displaces native ant populations in California and elsewhere and has become a significant agricultural pest, the researchers said.
Their findings, published in the journal Current Zoology, suggest that the unwillingness of Argentine ants to expose themselves to danger when weakened by hunger could possibly give them a competitive edge over other species by helping to preserve their colonies' foraging capabilities.
“While not foraging may lead to a reduction in food stores when those stores are already low, foraging in a high-risk environment exposes the colony to potential loss of foragers,” said the study's senior author, Noa Pinter-Wollman, a UCLA professor of ecology and evolutionary biology. “So reduced foraging could be interpreted as individual foragers not taking unnecessary risks.”
To support the energetic requirements of daily life, all ants require carbohydrates, which they obtain from a variety of plant and animal sources. They also need protein, which they generally get from dead animals, to nourish their larval offspring. Ant colonies adjust their foraging strategies according to the availability of these food sources, the presence of competing ant species, and the threat of predators or other dangers. Well-fed ants will forage for carbohydrates even in the presence of other ant species or danger cues.
First author Bryce Barbee, who conducted the research as a UCLA undergraduate, expected that starving Argentine ants of either carbohydrates or protein would only increase their willingness to forage for those foods in high-risk environments because they had little to lose and everything to gain.
Together with Pinter-Wollman, Barbee designed a series of laboratory experiments that involved feeding ants normally, depriving them of either carbohydrates or protein, and depriving them of both, then allowing them to forage as they normally would in either low-risk or high-risk environments.
The researchers created the impression of high-risk environments with formic acid, a chemical marker produced by ants, to signal the presence of competitors.
When the risk was low, starving ants did indeed forage more vigorously for the food of which they had been deprived. But when the risk was high, starving ants surprised the researchers by becoming more cautious, not less, in their foraging strategies.
In both high- and low-risk foraging scenarios, the ants were more willing to forage for carbohydrates than protein, which they only need to raise their brood. Since no eggs or pupae were present in the laboratory colonies, this finding might not be surprising, but it could also indicate that starving ants put their own energetic needs ahead of raising offspring, the researchers said.
Scientists who study animal behavior have advanced two ideas to explain foraging strategies. The first, known as the asset-protection principle, holds that hungry animals have less to lose than satiated animals and will therefore behave more assertively to get food. The second, the state-dependent safety hypothesis, holds that animals in good condition are more likely to take risks because they are more likely to survive dangers they encounter.
“Our work upheld the state-dependent safety hypothesis but not the asset-protection principle,” said Barbee, now a doctoral student at UC Santa Barbara. “The findings suggest that factors such as activity level and energetic costs of starvation are important for Argentine ant foraging decisions.”
The work points toward an avenue of research that could lead to better efforts to control the spread of Argentine ants and mitigate their detrimental impact on agriculture, the researchers said.
https://academic.oup.com/cz/advance-article/doi/10.1093/cz/zoac089/6825390
Ant species across five subfamilies exchange milk-like substances. Jasius via Getty Images
- Author: Kathy Keatley Garvey
Brazilian-born scientist Mônica Antunes Ulysséa, a postdoctoral fellow in the laboratory of Corrie Moreau, Cornell University, will speak on "Morphology for Assessing Species Diversity and Previously Unknown Biological Traits of the Ant Genus Hylomyrma" at a virtual seminar at 4:10 p.m., Wednesday, Dec. 7.
The Zoom link: https://ucdavis.zoom.us/j/95882849672. Host is doctoral candidate Jill Oberski of the Phil Ward laboratory.
"Hylomyrma is a Neotropical ant genus of small to midsized ants, cryptic inhabitants of the leaf-litter of wet and dry environments, with a remarkable body sculpture," she says in her abstract. "They occur from sea level to 3,600m, from Mexico to northern Argentina and southern Brazil; its higher diversity is in the Amazon. Out of the 30 recognized species, 11 have females whose external morphology combines morphological traits of workers and queens, and at least three of them present female specimens with queen-like traits. These mosaic specimens sent me back to fieldwork to investigate more about the genus biology. I went to Serra do Cipó, Brazil, to find nests of the endemic Hylomyrma primavesi. Hence, for the first time, the H. primavesi nest architecture and the colony size were documented, the ergatoid queen, male and immatures were collected, and the behavior of the forage workers and their feeding preferences based on field and lab observations were recorded."
Ulyssea specializes in myrmecology, taxonomy, phylogeny, systematics, curatorial practices, and science dissemination. She received a 2018-2023 postdoctoral fellowship at Zoology Museum of University of Sao Paulo (2018-2023) to study in the Moreau lab. Professor Moreau, who teaches arthropod biosystematics and biodiversity, directs and curates the Cornell University Insect Collection.
Ulyssea's resume includes:
- Doctorate from the Zoology Museum of University of Sao Paulo, Brazil, Graduate Program in Systematics, Animal Taxonomy, and Biodiversity (2013-2017)
- Internship at Sorbonne University, Pierre and Marie Curie Campus, Paris/France (2015-2016).
- Master's degree in zoology, Graduate Program in Zoology at the State University of Feira de Santana, BA/Brazil (2010-2012).
- Bachelor and licentiate in biological sciences at Federal University of Santa Catarina, Florianópolis, SC/Brazil (2002-2008)
Urban landscape entomologist Emily Meineke, assistant professor, coordinates the department's seminars. This is the last of the fall seminars. For further information on the seminars or technical difficulties with Zoom, contact Meineke at ekmeineke@ucdavis.edu.
- Author: Kathy Keatley Garvey
With the Entomological Society of America (ESA), however, being framed is a good thing. No, a great thing!
ESA honors its President's Prize winners (aka first-place winners) in the student research competitions by asking them to step behind a cardboard cut-out and smile for the camera. Voila! Suitable for framing!
Joe Rominiecki, ESA manager of communications, just announced that the images are now available and we have permission to share them.
We earlier wrote that doctoral candidates Danielle Rutkowski and Zachary Griebenow of the UC Davis Department of Entomology and Nematology each won the President's Prize for their individual research presentations at the 2022 Joint Meeting of the Entomological Societies of America, Canada, and British Columbia, held Nov. 13-16 in Vancouver, British Columbia.
And now, we have the images.
Background: At the annual ESA meetings, students are offered the opportunity to present their research and win prizes. They can compete in 10-minute papers (oral), posters, or infographics. The President's Prize winners receive a one-year paid membership in ESA, a $75 cash prize, and a certificate. Second-winners score a one-year free membership in ESA and a certificate.
Rutkowski, who studies with community ecologists Rachel Vannette, associate professor, and distinguished professor Richard “Rick” Karban, spoke on “The Mechanism Behind Beneficial Effects of Bee-Associated Fungi on Bumble Bee Health,” at her presentation in the category, Graduate School Plant-Insect Ecosytems: Pollinators.
Her abstract: "Bees often interact with fungi, including at flowers and within bee nests. We have previously found that supplementing bumble bee colonies with these bee-associated fungi improves bee survival and increases reproductive output, but the mechanisms behind these effects are unclear. This research aimed to determine the mechanisms underlying positive impacts of fungal supplementation in the bumble bee, Bombus impatiens. We tested two hypotheses regarding possible nutritional benefits provided by bee-associated fungi. These included the role of fungi as a direct food source to bees, and the production of nutritionally important metabolites by fungi. To test these mechanisms, we created microcolonies bumble bees and exposed each microcolony to one of four treatment groups. These four treatments were created based on the presence of fungal cells and the presence of fungal metabolites. We found that bee survival and reproduction were unaffected by treatment, with trends of decreased survival and reproduction when fungi were present. This contradicts previous results we've found using this bumble bee species, where fungi had a positive impact. It is possible that this disparity in results is due to differences in pathogen pressure between the two experiments, as bees in the first experiment were exposed to large amounts of pathogen through provided pollen, including Ascosphaera and Aspergillus. This pollen was sterilized for subsequent experiments, reducing pathogen load. Therefore, it is possible that bee-associated fungi benefit bees through pathogen inhibition, and future work exploring this hypothesis is necessary to fully understand the role of these fungi in bumble bee health."
Zachary Griebenow. Griebenow, who studies with major professor and ant specialist Phil Ward, (Griebenow also captained the UC Davis Entomology Games Team in its national championship win at the Entomology Games or Bug Bowl) explained “Systematic Revision of the Obscure Ant Subfamily Leptanillinae (Hymenoptera: Formicidae), Reciprocally Informed by Phylogenomic Inference and Morphological Data.” His category: Graduate School Systematics, Evolution and Biodiversity: Evolution 1.
His abstract: "Ants belonging to the subfamily Leptanillinae (Hymenoptera: Formicidae) are sister to nearly all other extant ants. Miniscule and subterranean, little is known of their behavior. Contrary to the collecting bias observed in most ants, male leptanilline specimens are acquired more easily than workers or queens. The sexes are almost never collected in association, and many subclades within the Leptanillinae are known from male specimens only. Our comprehension of evolutionary relationships among the Leptanillinae is further obstructed by oft-bizarre derivation in male phenotypes that are too disparate for phylogeny to be intuited from morphology alone. These restrictions plague our understanding of the Leptanillinae with probable taxonomic redundancy. My thesis aims at leptanilline taxonomy that reflects phylogeny, inferred from both genotype and phenotype, and integrates morphological data from both sexes. Here I present the results of (1) phylogenomic inference from ultra-conserved elements (UCEs), compensating for potential systematic biases in these data, representing 63 terminals; and (2) Bayesian total-evidence inferences from a handful of loci, jointly with discrete male morphological characters coded in binary non-additive or multistate fashion. Notably, these analyses identify worker specimens belonging to the genera Noonilla and Yavnella, which were heretofore known only from males. Given such discoveries across the Leptanillinae, the number of valid leptanilline genera is reduced from seven to three in order to create a genus-level classification that upholds monophyly along with diagnostic utility."
We also salute our second-place winners (see previous news story:
- Lindsey Mack, who studies with medical entomologist-geneticist Geoffrey Attardo, assistant professor, covered “Three Dimensional Analysis of Vitellogenesis in Aedes aegypi Using Synchrotron X-Ray MicroCT” in the category, Graduate School Physiology, Biochemistry and Toxicology: Physiology
- Addie Abrams, who studies with Extension agricultural entomologist and assistant professor Ian Grettenberger, titled her research, “Hitting the Mark: Precision Pesticide Applications for the Control of Aphids in California Lettuce" in the category, Graduate School Physiology, Biochemistry and Toxicology: Integrated Pest Management
Congrats, all! They do our department and our university proud!
(The 7000-member ESA, founded in 1889, is the largest organization in the world serving the professional and scientific needs of entomologists and individuals in related disciplines. Its members, affiliated with educational institutions, health agencies, private industry, and government, are researchers, teachers, extension service personnel, administrators, marketing representatives, research technicians, consultants, students, pest management professionals, and hobbyists.)
