Undersøgelse viser adfærdsmæssige, fysiologiske ændringer hos myrer forstyrret af udvikling, byspredning

Forskning udført af Texas A&M AgriLife Forskere i Texas A&M Department of Entomology viste, at en almindelig myreart gennemgår fysiologiske og adfærdsmæssige ændringer i unaturlige omgivelser.

"Konsekvente signaturer af urban tilpasning i en indfødt, urban invader ant Tapinoma fastsiddende," offentliggjort i Molecular Ecology, inkluderet arbejde af hovedforfatter Alexander Blumenfeld, en tidligere kandidatforskningsassistent; Ed Vargo, Ph.D., seniorforsker og begavet formand for by- og strukturentomologi; Anjel Helms, Ph.D., en kemisk økolog og adjunkt; og Pierre-André Eyer, postdoktoral forskningsassistent, alle ved Institut for Entomologi.

"Urbanisering er et voksende habitat rundt om i verden, og det bliver vigtigere for organismer at udvikle måder at leve på, når deres naturlige omgivelser er forstyrret," sagde Vargo. "Undersøgelser som dette ser på vigtige spørgsmål vedrørende denne ændring:'Kan de tilpasse sig bymiljøer og hvordan?'"

Miljøet påvirker myrernes adfærdsmæssige, kemiske ændringer

Undersøgelsen fokuserede på Tapinoma sessile, en relativt lille myreart, almindeligvis kendt som husmyren eller sukkermyren. Det er den mest almindelige husinvaderende myre i hele USA.

I sit oprindelige miljø skaber husmyren små enkeltdronningkolonier, der typisk findes under bladaffald, sten og træstammer, sagde Vargo. Men i forstæder/bymæssige omgivelser bygger disse husmyrer stadigt ekspanderende kolonier med flere dronninger omkring menneskeskabte strukturer såsom fortove, plantebeholdere og landskabsmulching.

Vargo sagde, at undersøgelsen giver en bred vifte af videnskabelig anvendelse relateret til biologiske og adfærdsmæssige ændringer ansporet af miljøforhold i hele dyreriget. Det kunne også give indsigt i, hvordan invasive arter interagerer med miljøer, der er nye for dem.

"Ændringen ligner meget invasive myrer, når de flytter fra deres oprindelige område til et invasivt område," sagde han. "Idéen er bedre at forstå dette syndrom hos en myreart, der kan tage en lille, upåfaldende koloni, som så bliver et økonomisk og økologisk problem, når skadelige kolonier bliver større og større."

Besvarelse af spørgsmål om adaptiv evolution

Researchers utilized a large genetic database to identify the chemical and behavioral changes that influenced the ants' social organization, Vargo said. They explored and compared the population genetics and breeding structure within and between ants in several urban and undisturbed natural locations within their range.

Odorous house ants were observed and analyzed in natural and disturbed locations around the country including Indiana, Arkansas, Colorado and California.

The team analyzed the ant's chemistry, such as hydrocarbons, genetic makeups of colonies and behaviors, such as aggression toward familial and outsider ants, and found stark differences based on the environment, Vargo said.

The study found that house ants in urban and natural areas showed adaptations that resulted in genetic concentration. Vargo said house ant queens in their natural habitat typically leave the colony they were born in, fly to another suitable location and attempt to establish a new colony. Queens in urban colonies stay in the nest and expand the colony rather than leave.

As a result, urban queens were closely related and less aggressive toward ants with genetic relation. Behavioral analyses showed ants in super-colonies were aggressive toward ants with outside genetics.

Additionally, polydomous colonies, which are ant colonies that are spatially separate but socially connected, were only present in urban habitats, Vargo said. This suggests house ants only create super-colonies in developed areas. Ants from different urban areas shared some genetic similarities, suggesting they are adapting to features that are common in the urban environment.

As a next step, researchers plan to compare stable isotopes in the ants to look at dietary changes and how they might relate to natural vs. urban environments and possible contributing factors like temperature and the urban heat island effect.

Vargo said the researchers have hypotheses but no data yet linking how and why changes occurred.

The research was initiated by Blumenfeld, who was a doctoral student in Vargo's lab and is now a post-doctorate researcher at Yale University. He said he is interested in answering questions related to adaptive evolution in animals regardless of classification or species, and whether they are invasive or adapting to human-caused disturbances, including cities.

"The study highlights urbanization's influence on the evolutionary course for species," he said. "It's important for us to answer questions related to adaptive evolution, whether it is an invasive species or a forest species adapting to city environments." + Udforsk yderligere

Tawny crazy ants' weird genetics may help them thrive in new environments