LAUSR

Dear Dr. Hurd In a recently published AESA review article by Leal et al. (2020), there are two substantive errors and an omission. The first error is where the article mistakenly claims, citing Showler et al. (2018), that the consumption of tick eggs by mudflat fiddler crabs, Uca rapax Smith, is a hypothesis and that the crabs have not been observed taking and eating tick eggs. Showler et al. (2018) reported in the Results section: ‘Observations while conducting ant and U. rapax field sampling included U. rapax feeding on ixodid egg masses and on hot dog slices. When U. rapax were observed feeding on egg masses, the crabs most often quickly retreated from the eggs to their holes in our presence. We found some egg masses that had been broken apart and small clusters were scattered in the direction of a U. rapax hole,’ and ‘after one night, each bucket containing seven U. rapax had no A. americanum eggs left. In the control buckets, all of the egg masses remained. The crabs frequently displayed feeding behavior on the mud in the buckets with and without A. americanum eggs, presumably consuming food items embedded in the mud other than the tick eggs. Uca rapax began feeding on eggs in 1–5 min. Individuals moved adjacent to the mass and repetitively transferred eggs, one or several at a time, using the small pincer (not the opposing “fiddle” pincer).’ The direct observations were augmented by the overnight disappearance of ≈80% of tick egg masses in U. rapax habitats (constituting ≈25% of the study region) when disappearance of eggs was negligible in other habitats, dense U. rapax populations, and negligible larval tick populations in U. rapax habitats in contrast to relatively robust tick populations in habitats without the crabs (Showler et al. 2018). Leal et al. (2020) also indicated that ants attack ticks. While that might be true of some tick species, it is not true of metastriate ixodids, comprising the genera Amblyomma, Dermacentor, and Rhipicephalus (Yoder et al. 1992, 2009; Yoder and Domingus 2003). Showler et al. (2018) showed that none of the ant species encountered in their tick ecology study attacked lone star tick, Amblyomma americanum (L.), eggs. In a different study, Showler et al. (2019) demonstrated that A. americanum eggs, larvae, nymphs, adults, and engorged adults, were not attacked by any of eight species of predatory ants, including the red imported fire ant, Solenopsis invicta (Buren), in three different regions of Texas. In the instance of red harvester ants, Pogonomyrmex barbatus (F. Smith), engorged adult A. americanum were transported away from the colony entrance for disposal (all other life stages were ignored). Showler et al. (2019) was also highlighted in Entomology Today in an article titled ‘How ticks hide in plain sight from predatory fire ants’, published in October 2019, https://entomologytoday. org/2019/10/02/how-ticks-hide-plain-sight-predatory-fire-ants/. An earlier study conducted on the South Texas coastal plains indicated that S. invicta actually drives small mammalian and avian tick hosts from the infested areas, causing an associated drop in tick numbers (Castellanos et al. 2016). Last, Leal et al. (2020) discussed abiotic factors but did not mention that saline and hypersaline water, even applied as a one-pulse mist, are extremely lethal to tick eggs (Showler et al. 2018). On the other hand, saline soil is not necessarily toxic to egg masses in contact with it (Showler et al. 2018). The lethality of saline water is important because it occasionally inundates (from wind tides and storm surges) ≈25% of the South Texas coastal plains wildlife corridor where southern cattle fever ticks, Rhipicephalus microplus (Canestrini), are currently being encountered on vegetation, evidence that the species is completing its life cycle there (Osbrink et al. 2020). During times when the infrequently inundated areas are dry or moist, tick eggs can survive on the soil as long as relative humidity is sufficiently high (Showler et al. 2018). The problem, for the ticks, is that saline areas, even when dry, are the habitat of U. rapax.