The Tactics of an Egg Tending Lynx

While stomping through a northwest Florida flatwoods community earlier this week, I took pause to admire a couple of swamp sunflowers (Helianthus angustifolius). The sunflowers’ brilliant yellow display glared brightly through the otherwise dark and rainy Tuesday afternoon and beckoned for a closer look. On turning-over one of the composite flower heads to better examine its calyx, I discovered a green lynx spider (Peucetia viridans). The spider was standing guard on top of its egg sac, which it had tethered securely to the optimistic sunflower’s underside with hard-wearing silk.

The green lynx spider is a member of the Oxyopidae Family and accordingly displays several traits characteristic for the group. In terms of identifying morphology, members of the group show a hexagon-like pattern of eye arrangement, and legs that bear large spines. Behaviorally, members of the Oxyopidae are aggressive daytime hunters which, as opposed to constructing webs, stalk their prey over the leaves and stems of the herbaceous groundcover. In regards to Peucetia viridans specifically, the spider’s body is translucent and exhibits a bright green coloration with red spots on the cephalothorax and black spots on its spiny legs.


Considering the presence of an egg sac and the sentinel-like bearing demonstrated by the spider appended to the sunflower, it was very likely a female. As a strategy, females of the species uncompromisingly guard their reproductive investment using a variety of tactics. These protective measures are necessitated by the low-to-the-ground habitat they share with a number of other voracious predators. Here in Florida, some of the most abundant and hostile species encountered by lynx spiders are fire ants (Solenopsis spp.)

The specific tactic used to defend an egg sac from fire ant onslaught is dependent on the intensity of the ant attack. Intensity is here a measure of ant quantity and the frequency of assault. Generally, female lynx spiders will utilize a mode of defensive escalation in which infrequent or isolated attacks from a single ant will be dealt with through deployment of a rapid and violent head-on confrontation. As the ant approaches the female, she’ll pounce forward and use her mass to knock the assailant from the plant, or, if failing to physically remove the ant, she’ll alternatively utilize her fangs to pierce the exoskeleton of her antagonist, ultimately slaying the provoker. The spider will almost always prevail during one-on-one combat with an ant, however if the ant attack is undertaken in number, evasion becomes the best option for the lynx.

If the incidences of attack become too frequent, or if the ants attack in larger quantities, mother Peucetia viridans will attempt to dissuade the egg-seeking aggressors by removing the prize for which they hunger – she’ll move the eggs out of reach. Once again depending on the seriousness and intensity of the ants’ offensive maneuvers, she’ll execute one of two evasive actions. One option is to cut all but a couple of the silk cables holding the egg sac in place, causing it drop from its anchor point and remain suspended in air; the second option to completely untie the sac and relocate to an entirely new host plant. The suspension method removes the eggs from hostility and forces any persistent attackers to travel down individual threads to continue pursuit – where they’ll undoubtedly meet an agitated mother face-to-face. Relocating the egg sac to a new host is a sure-fire way to end the current dispute however it is a risky option, because increased visibility during transport may leave both the mother and her eggs vulnerable to other hungry predators.


Eubanks, M. (2001). Estimates of the Direct and Indirect Effects of Red Imported Fire Ants on Biological Control in Field Crops Biological Control, 21 (1), 35-43 DOI: 10.1006/bcon.2001.0923

Linda S. Fink (1987). Green Lynx Spider Egg Sacs: Sources of Mortality and the Function of Female Guarding (Araneae, Oxyopidae Journal of Arachnology, 15 (2), 231-239

Fire Ants Attack - Lizards Adapt

Fire ants (Solenopsis) are an invasive species in the US, and they’re a big problem here in Florida – there are no less than two nests in my backyard at any given time. Their hunger for new territory and their proclivity towards violence has resulted in conflict on more than one occasion. Although, thousands have been slain locally (and righteously, in my view) the battles are ongoing – and I have more than one scar on my legs and feet to attest to this brutal history!

I’ve battled Solenopsis not for glory, but for the safety of the other backyard fauna; massacred frogs, fledgling birds and anoles have all been discovered – Kitsune and Zita (my dogs) have also endured the wrath and sting of these imperialists…

OK, OK – I’ll stop with the war metaphor.




In all seriousness these gals are hardy to say the least. My understanding is that their rate of expansion into North America is driven by a genetic discrepancy between the invading lineages and those native to South America that has resulted in social polymorphism. In Argentina, Solenopsis queens emit a pheromone that identifies her to the colony – make way for the queen! If a foreign queen should enter the colony, workers detect the foreign pheromone and quickly dispatch her (essentially she’s drawn and quartered). In contrast, a genetic mutation in the DNA of the US invasive variety has altered a pheromone binding protein (Gp-9) to such extent that invasive queens are no longer recognized by workers. Because of this, a single colony in the US may have multiple reproductive queens (polygyny) coexisting at the same time – reproductive rates go through the roof.

{This pic shows the colony "rafting" following flooding}

The pheromone recognition behavior, when functioning, has the affect of geographically limiting the proximity of any two colonies. This results in fewer individual colonies per a given area. When, due to mutation, foreign queens aren’t recognized, inter-colony conflicts don’t occur as frequently thereby opening the door to “super colonies” and shared territories.

This mutation is positively selected in the relatively open ecosystem of the US; however as Solenopsis populations continue to raise their numbers may reach a threshold that gives advantage to the more territorial variety (monogyny), this may push the species towards more geographic balance, as is evident in the South American native type.

I bring up Solenopsis because I just read a Science Daily article discussing how native lizards in the southeastern United States are adapting to potentially fatal invasive fire ant attacks by developing behaviors that enable them to escape from the ants, as well as by developing longer hind legs, which can increase the effectiveness of this behavior. This according to Penn State Assistant Professor Tracy Lang Penn, recently published in the journal Ecology

Here’s a nifty little video from Penn’s website showing a noosed lizard flicking away attacking Solenopsis - FYI the video skips for the first couple seconds:

Better the lizard than me! Solenopsis are aggressive, they like to lock on with their mandibles and sting multiple times – with painful and skin blistering alkaloid venom, Ouch!

Tracy Langkilde (2009). Fence Lizard Bulletin of the Ecological Society of America, 90 (1), 36-37 DOI: 10.1890/0012-9623-90.1.36

M. J. B. Krieger (2005). Molecular Evolutionary Analyses of the Odorant-Binding Protein Gene Gp-9 in Fire Ants and Other Solenopsis Species Molecular Biology and Evolution, 22 (10), 2090-2103 DOI: 10.1093/molbev/msi203