Winter hatching in New England populations of invasive pheretimoid earthworms Amynthas agrestis and Amynthas tokioensis: a limit on population growth, or aid in peripheral expansion?

Görres, Josef H.; Connolly, Samantha T.; Chang, Chih-Han; Carpenter, Nell; Keller, Erin L.; Nouri-Aiin, Maryam; Schall, Jos. J.

doi:10.1007/s10530-018-1663-x

Cited by 15 publications

(5 citation statements)

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“…The two Amynthas invasive species are epi-endogeic, and both over a single warm season and across years there were variable moisture conditions, and unpredictable changes in soil temperature, thus presenting a challenge for any introduced earthworm species ( Snyder, Callaham & Hendrix, 2011 ; Görres et al, 2018 ; Nouri-Aiin & Görres, 2019 ). The great success of the Amynthas earthworms could be explained in part by a mixed reproductive system.…”

Section: Discussionmentioning

confidence: 99%

“…There are hundreds of species of Amynthas widely distributed in Asia, and 16 have been introduced to North America, yet only three are considered to be widely invasive. Several characteristics of the invasive Amynthas earthworms have been proposed to aid entry into established soil communities, including a broad diet ( Zhang et al, 2010 ), tolerance of their eggs and embryos within a covering cocoon to drought and cold ( Görres et al, 2018 ), and suspected parthenogenesis and polyploidy ( Hendrix et al, 2008 ; Minamiya et al, 2011 ). Earthworms are typically hermaphrodites, but both A. tokioensis and A. agrestis often lack some of the male reproductive structures including spermathecal pores, spermathecae, male pores, prostate glands, and their associated genital markings ( Chang, Snyder & Szlavecz, 2016 ), which strongly suggests they have abandoned the male function and reproduce parthenogenetically ( Chang et al, 2021 ).…”

Section: Introductionmentioning

confidence: 99%

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Genetic population structure and reproductive system of two invasive Asian earthworms,Amynthas tokioensisandAmynthas agrestis

Nouri-Aiin

Connolly

Keough

et al. 2022

PeerJ

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The invasive Asian earthworms, Amynthas tokioensis and A. agrestis, have been successful in entering North American forests in recent decades, with significant damage to both soils and above-ground environments. This success could be driven in part by a polyploid genetic system and parthenogenetic reproduction, often suggested as benefits for invasive species. Therefore, we assessed the genetic population structure, genetic diversity, and reproductive system of both species using morphological traits and panels of microsatellite markers. A total of 216 A. tokioensis and 196 A. agrestis from six sites in Vermont USA were analyzed. Although all worms were morphologically hermaphroditic, all the A. agrestis lacked the male pore (the structure allowing pass of sperm between individuals), and only 19% of the A. tokioensis possessed the male pore. All A. tokioensis earthworms were triploid (scored for three alleles for at least 1 locus, and usually several), and A. agrestis was a mix of triploid and diploid individuals. Notable was the high proportion (80%) of A. agrestis earthworms that were diploid at one site. There was clearly clonal reproduction, with identical seven- locus genotypes observed for earthworms from each site, with as many as 45 individuals with the identical genotype at one site. However, the earthworms were also genetically diverse, with 14 genotypes observed for A. tokioensis and 54 for A. agrestis, and with many singleton genotypes (a single individual). Most genotypes (71% for A. tokioensis and 92% for A. agrestis) were found at a single site. The greatest number of genotypes was found at a commercial nursery where fully 23/26 A. agrestis earthworms were singleton genotypes. As expected for the pattern of private clone alleles at sites, several measures of geographic genetic differentiation were positive, and as expected for triploid systems, an AMOVA analysis showed high within-individual genetic diversity. The paradox of clear clonal reproduction, but with a great number of genotypes for each species, and the mix of triploid and diploid individuals could be explained if the worms have been sexually reproductive, with the switch to the uniparental system only recently (or even if sexual reproduction is episodic). Last, a large number of microsatellite loci were recovered for each species and there sequence and suggested PCR primers are provided for free use by other researchers.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Genetic population structure and reproductive system of two invasive Asian earthworms,Amynthas tokioensisandAmynthas agrestis

Nouri-Aiin

Connolly

Keough

et al. 2022

PeerJ

Self Cite

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“…The three most important pheretimoid invaders are annual earthworms which require about 90 days from hatchling to maturity ( Görres & Melnichuk, 2012 ). However, hatching occurs year-round ( Görres et al, 2018 ; Nouri-Aiin & Görres, 2019 ) and peak abundance is usually achieved in late May or early June in Vermont, this may vary with climate zone, and the rate of accumulation of heat unit ( Görres, Bellitürk & Melnichuk, 2016 ). First adults are observed in early June to mid-August ( Görres, Bellitürk & Melnichuk, 2016 ; Nouri-Aiin & Görres, 2019 ).…”

Section: Discussionmentioning

confidence: 99%

“…Of the 16 pheretimoid species known to be present in North America ( Chang, Szlavecz & Buyer, 2016 ), three frequently co-invade in North America: Amynthas agrestis , A. tokioensis and Metaphire hilgendorfi ( Chang et al, 2018 ). The northerly expansion ( Moore, Görres & Reynolds, 2018 ; Görres et al, 2018 ) of the three co-invading pheretimoid species may be due to the lengthening of the growing season in the past 30 years ( Hayhoe et al, 2007 ; Bohlen et al, 2004 ). Although the invasive earthworm research focus has been on forested ecosystem, damage has been reported from nurseries and greenhouses, where the worms invade pots and production beds.…”

Section: Introductionmentioning

confidence: 99%

Biocontrol of invasive pheretimoid earthworms using Beauveria bassiana

Nouri-Aiin

Görres

2021

PeerJ

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Background Invasive species cause enormous costs of over $120 billion to the U.S. economy. Among biological invasions, the invasion by pheretimoid earthworms has gone relatively unnoticed and their invasion imposes yet unknown damage on USA agriculture and horticulture. The main dispersal is with horticultural goods such as plant material and composts. Pheretimoids affect commercially important hardwood forest. With no chemical agents currently certified for earthworm control nor any best horticultural practices, slowing the invasion is difficult. Methods In this study we measured the efficacy of a commercial entomopathogenic fungal isolate of B. bassiana (BotaniGard®) to kill pheretimoid earthworms under greenhouse conditions. Four treatments of B. bassiana were applied: The commercial product as per label, re-cultured commercial B. bassiana, 15 g and 25 g millet grains mycotized with recultured product. In all, three bioassays were conducted in 2 consecutive years with two batches of BotaniGard®. Results With fresh batches, all B. bassiana treatments with re-cultured product resulted in greater than 70% mortality within 4 weeks. Mortality was less than 60% when BotaniGard® was used as prescribed by the label. When using 1-year old spores (refrigerated at 4 °C), mortality rates for B. bassiana treatments were less than 20% and not significantly different from the controls. However, B. bassiana still affected the earthworms by slowing their development from juvenile to adult stage. Conclusion B. bassiana was effective against pheretimoid earthworms. Overall, mycotized millet grains did not significantly increase mortality over the re-cultured, directly applied B. bassiana spores. More experimentation is needed to find the mode of action of the re-cultured B. bassiana before investigating ways to improve the efficacy of B. bassiana when applied as prescribed on the label.

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“…and soybean aphid ( Aphis glycines Matsumra). Some exotic earthworms can benefit agriculture but may experience mortality when emerging during a false spring (Görres et al, 2018). Therefore, we should evaluate what soil conditions promote or decrease soil buffering capacities to protect soil fauna.…”

Section: Knowledge Gaps—direct and Indirect Effectsmentioning

confidence: 99%

Need for False Spring Research in the Northern Great Plains, USA

Kral‐O'Brien¹,

O’Brien

Harmon³

2019

Agricultural & Env Letters

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Global climate change is typically characterized by warming average temperatures and more frequent extreme weather events. An understudied component of climate change is the occurrence of false springs, where warm temperatures in early spring prematurely release plants from dormancy, only to be harmed by a late spring frost event. Only limited research has investigated the nature, extent, and impacts of false springs, despite their potential for extreme environmental and economic consequences. More resources should be devoted to false spring research because they are predicted to increase in several regions, especially the northern Great Plains. We review the existing literature on false springs and identify knowledge gaps in both cropland and natural systems. Further, we propose avenues of research, focusing on ecosystems of the northern Great Plains. This research will be crucial in creating strategies that allow land managers to adapt to changing conditions caused by more frequent false springs.

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Winter hatching in New England populations of invasive pheretimoid earthworms Amynthas agrestis and Amynthas tokioensis: a limit on population growth, or aid in peripheral expansion?

Cited by 15 publications

References 14 publications

Genetic population structure and reproductive system of two invasive Asian earthworms,Amynthas tokioensisandAmynthas agrestis

Genetic population structure and reproductive system of two invasive Asian earthworms,Amynthas tokioensisandAmynthas agrestis

Biocontrol of invasive pheretimoid earthworms using Beauveria bassiana

Need for False Spring Research in the Northern Great Plains, USA

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