7 replies to this topic

[futurebird]

The biggest and most beautiful oak trees in the south bronx always have a carpenter ant colony and likewise these ants are only ever found in the very best of the trees. 

So I decided to look up "carpenter ants and oak trees" to find out more about their relationship and you must imagine my horror at being offered pest control serviced to "protect" an oak tree from a "carpenter ant attack"

--Now I do have a pro-ant bias, but this seems... unlikely. Especially because you never see carpenter ants in young oak trees (or in spindly unhealthy trees) they like the older trees and I assumed this was because such trees would have natural hollows and nesting spaces, as well as retaining heat in the cold and moisture on hot days... likewise a large leafy oak is home to many creatures that the carpenter ants would enjoy having for their meals... alongside the steady diet of sweets they find easily since these are NYC ants who have all the sugar they want. 

But, I thought I'd check. 

Can carpenter ants harm an oak tree?

[PurdueEntomology]

I personally am unaware of any specific unique relationships between ants of the genus Camponotus and trees of the genus Quercus save for C. vafer (see below).  Though many endemic species of Camponotus  will excavate galleries in trunks and branches and live at the bases of oak, depending on the size of the tree and the size of the ant colony I suspect there is little lethal effects of the ants on the trees. [I have found no published papers on this topic specifically] As various oaks are often dominate in North American forests it is not surprising to see carpenter ants using these trees as nest locations. As oaks are often the host plants for various arthropods they are also excellent hunting grounds and sources of "honey dew".  The only species  that is nest-host specific to oaks is C. vafer which is found from Texas to Arizona.  More on this is found at Taxonomy of the Camponotus festinatus complex in the United States of America (Hymenoptera: Formicidae) (SNELLING, 2006)

Edited by PurdueEntomology, April 6 2023 - 1:31 PM.

[ReignofRage]

I've found a significant (four figure) amount of Camponotus colonies in very young oak trees (as small as 5cm in diameter), diseased oak trees, unhealthy oaks, and dying oaks. For the most part, Camponotus founding gynes will usually hollow out a cavity made by termites, beetles, etc. However, I have observed multiple species' gynes excavating their own chamber in living wood. In addition, I do not doubt that colonies will excavate living wood given that preexisting galleries and tunnels are not large enough to house the colony. Will it kill a tree? I find it unlikely. 

Edited by ReignofRage, April 6 2023 - 1:35 PM.

[Flu1d]

A Camponotus floridanus colony(ies) dominates the giant, very old southern live oak tree in my back yard, as well as some of that very oaks smaller children around my fenceline. I also sometimes see discolor/decipiens workers (I have not been able to identify which, if not both.. Although I believe it is hairs that separate the species) as well as C. snellingi workers.. However not in the same capacity or numbers as C. floridanus.

I have yet to find any other Camponotus species, unfortunately.. however I must say the ones I have spotted love oak. So do the local Pseudomyrmex species.. specifically gracilis and ejectus.

EDIT: I forgot to add that there is significant damage from the floridanus on the tree. That being said, it was split almost in two by a lightning strike when hurricane Ivan hit in 2004 so I don't know how well the tree was doing right before they got ahold of it, anyway.

Edited by Flu1d, April 6 2023 - 5:55 PM.

[rptraut]

Many large oak and maple trees have large crotches where branches join the main trunk.  Water tends to accumulate in these areas and seeps into the wood, leading to rot.  Water also soaks into areas where the bark is damaged, softening the wood and leading to rot.   Camponotus ants find these prime locations for nesting and their tunnels and excavations further increase water penetration and therefore rot deeper into the tree.  Although this rot may not kill the tree directly, it ultimately becomes a fatal flaw that weakens the tree which often then succumbs to increased damage from wind, snow and ice.    I have had to fell trees that suffered from such damage and at the heart of the rot, there is always a Camponotus nest.

[Manitobant]

At least in my area, camponotus pennsylvanicus nest almost exclusively in the trunks and bases of oak trees. I have yet to find a nest anywhere else.

[MrILoveTheAnts]

It goes without saying Camponotus who nest in wood (either exclusively or mixed with the soil) need wood in order to found colonies and persist in the area. Oaks are probably the most successful genus in North American forests. They make up something like 30% of the trees and occur in a wide range of habitats. This is largely thanks to Blue Jays collecting and dispersing the acorns far and wide. There are oaks for mountains, wetlands, sandy pine barrens; there's even a creeping ground cover species out west. And they are a fountain of resources too. 

 

More than 500 species of Lepidoptera (moths and butterflies) use oaks as hosts which is a whole lot of ant food over the course of the year. Even in winter they've found the stomachs of dead birds are often full of caterpillars that mimic twigs, specifically the ones that host on oak trees. They're just stuffed into the bark in winter and they're there to munch on the leaves once the weather warms up. An even greater number of Gall wasps use oak trees as hosts resulting in odd sorts of growths on the leaves. Some of these produce nectar or dew, or later when they drop off the tree have a small food body on them to encourage the ants to move them about. Oak leaves get aphids too as well as leaf hoppers, tree hoppers, and scales that all produce sugary treats for ants to buy their protection. The acorns get weevils in them and once they drop off the tree these grubs less than a half hour to exit the acorn and burrow into the soil before getting eaten by something. If you ever look under an oak tree that's dropped it's acorns it's often a massacre of dead acorns. The ones the weevils haven't hollowed out are eaten by rodents and deer, and it's really only the ones hidden away by Blue Jays that make it to grow into trees, but even then the bird is doing that so it can eat them.

[Flu1d]

What an amazingly informative read. I really was not expecting to learn so much,yet I am so glad that I did. I have adored oak trees because I grew up climbing the very oak tree in my back yard today. This is the same home my parents used to own, and now I live here myself. I have very fond memories of climbing this tree and jumping out.. finding cool bugs on it, etc.

Thanks for all of the cool information!