Pomacea diffusa Blume, 1957 [Spiketop Applesnail] In Duval County, Florida

Fresh dead Pomacea diffusa

Fresh dead Pomacea diffusa

Fresh dead Pomacea diffusa collected near the dam in Lantana Lakes on 12/19/2006 and 12/20/2006, respectively

     During a trip to the post office (Pottsburg Branch, 11700 Beach Boulevard) on 17 December, 2006, this investigator  noticed what appeared to be apple snails egg clutches on a culvert spanning a nearby drainage ditch which ran south between the post office and the adjacent Sam's Club. As time was short, further investigation was postponed to the next day. Upon my return the next afternoon, it was confirmed that Pomacea paludosa (Say, 1829) Florida Applesnail egg clutches were present as well as those of another unidentified apple snail species. None of the egg clutches appeared to be fresh; therefore it appears likely they were deposited during the spring egg laying period. A thorough search of the full length of the ditch south of Beach Boulevard failed to reveal any live apple snails of any ilk. However, four empty Pomacea diffusa shells and one P. paludosa shell were found near where the ditch intersects Beach Boulevard.

One of several culverts where egg clutches were found

View towards Beach Blvd. where the shells were found

One of several culverts where egg clutches were found

View towards Beach Blvd. where the shells were found

Looking south adjacent to the Sams parking lot

Looking south adjacent to the Sam's Club parking lot

    During a return visit on December 19th, the upstream portion of the ditch north of Beach Boulevard was thoroughly investigated. The ditch continues north from Beach Boulevard adjacent to Lantana Lakes Drive (Lantana Lakes Subdivision) for about 175 yards before crossing west under the road and continuing a like distance before intersecting a small dam which impounds the subdivisions series of medium sized lakes. Empty Pomacea diffusa shells were found throughout most of this approximately 350 yard distance. However, they were especially common just below the spillway of the small dam where two recently deceased specimens with partial remains of the animals present were found. A much more modest number of P. paludosa shells were also found and no egg clutches produced by either species were seen. The three largest of the Lantana Lakes Subdivision lakes were then investigated and no living or dead specimens of either Pomacea species were seen although a few P. paludosa egg clutches were found on a culvert at the south end of the northernmost lake.

    On December 21st the downstream portion of the ditch below the Sam's Club was reconnoitered with the first easy access being a somewhat rickety wooden bridge over the waterway on Donnawood Drive inside the large Countryside Village Trailer Park. The remnants of three Pomacea diffusa egg clutches were subsequently found on one of the bridge pilings.  A search of the ditch in this area, as well as downstream for a considerable distance, failed to yield any Pomacea diffusa shells or egg clutches although a single empty Pomacea paludosa shell was found.

    Several additional visits to the habitat were subsequently made, and finally on 12/30/2006, a live juvenile P. diffusa was found inside a concrete culvert on Lantana Lakes Drive. The same date, a fresh dead adult specimen with the operculum and an animal intact was also found in the same general area. Having confirmed that live specimens were in fact present, on 1 January, 2007 a much smaller upstream portion of the drainage system east and immediately adjacent to Beach Boulevard (about 125 yards in length) was investigated. A single live adult Pomacea diffusa was found as well as the shells of other deceased specimens. On 1/10/2007, this reporter, along with Dr. Patrick Baker (University of Florida/IFAS), made a further investigation of the ditch during which time two additional live tiny juvenile specimens and one live adult specimen were found.

    With Pomacea sp. egg spring laying season well underway, the drainage ditch immediately adjacent to the SAM's Club was closely inspected on May 7, 2007 and 16 recently deposited Pomacea diffusa egg clutches were seen on bank vegetation and a single live adult specimen was collected in the same area thus confirming that a robust breeding population is present. Interestingly, no Pomacea paludosa egg clutches were seen. Subsequently on May 18th, the ditch below the dam in the Lantana Lakes Subdivision was investigated and four freshly deposited P. diffusa egg clutches were seen there thus confirming that a breeding population is present there as well. The ditch just north and immediately adjacent to the trailer park was then investigated the following day and six empty P. diffusa shells and a single egg clutch were found there although no evidence of the species could be located within the trailer park.

    Based on a variety of factors to include the total "known distance" of the drainage system colonized by the snails (over 1,400 yards), the number of dead specimens present, and the weathering of some of these specimens, it appears almost certain that the snails have been present in this habitat for many years. However, no evidence has been found to indicate that the snails have spread further downstream than the northern end of the trailer park. The aggressive "manicuring"  of vegetation in and adjacent to the ditch within the trailer park may have deprived the snails of suitable structure to deposit their egg clutches and thus propagate.

    The entire drainage system colonized by the snails was actively monitored throughout 2007 - culminating with a final visit on 12/30/2007. It had been believed that Pomacea diffusa, like the native Pomacea paludosa of which it shares the habitat, deposited egg clutches only during the spring months. However, this final 2007 visit revealed many freshly deposited Pomacea diffusa egg clutches on concrete structures throughout the habitat. It's uncertain if this is normal behavior or as a result of unusually warm winter weather conditions.

    Monitoring of the Pomacea habitat continued periodically throughout 2008 and 2009 (see Predation On Pomacea diffusa for some observations). Ultimately on 6/25/2009, during the prime egg laying period, a number of egg clutches were discovered on structure in the drainage ditch between the Kentucky Fried Chicken restaurant and Beach Boulevard (see image) thus extending the snails known habitat about 80 yards to the east and upstream in the ditch. In retrospect it is believed that the Pomacea diffusa had been present in this portion of the ditch for a number of years and evidence of their presence was simply overlooked. This range expansion brings the total length of the drainage system known to be colonized by the snails to about 1,500 yards.

Quite by accident on 7/10/2010 during a search for terrestrial species, a single freshly deposited Pomacea diffusa egg clutch was discovered on a concrete culvert at a small ditch on St. Johns Industrial Parkway South - a ditch that is part of the same drainage system but considerably "downstream" from the earlier P. diffusa finds spanning the years 2006-2009 (See map, bottom right). This  discovery roughly doubles the known length of the drainage system colonized by the snails. The location was checked periodically during 2011-2012 and during July, 2012 a single live Pomacea diffusa plus a number of fresh egg clutches were found.

    Since Pomacea diffusa is an especially popular aquarium trade species available in a wide variety of colors including so called gold, ivory, and blue, it's quite likely that their presence in the ditch is a result of a Lantana Lakes Subdivision resident discarding (dumping) unwanted specimens. Pomacea diffusa has been a popular aquarium species in Florida for over half a century and has been found in the wild here since at least 1965 (see:  Clench, W. J., 1965 Pomacea bridgesii (Reeve) in Florida. The Nautilus 79(3): 105. Jan.). Available information (1/07) indicates that the species has been found in the wild in Miami-Dade, Palm Beach, Broward, Alachua and Hillsborough Counties in addition to the Duval County find.

Note:  Pomacea diffusa was originally described by Blume in 1957 as a subspecies of Pomacea bridgesii based on specimens collected in Santa Cruz, Bolivia ( see holotype & paratype). Pain [1960] argued that P. bridgesii bridgesii was a larger form with a restricted range, with the smaller P. bridgesii diffusa being the common form throughout the Amazon Basin (Brazil, Peru, Bolivia). Cowie and Thiengo [2003] suggested that the latter might deserve full species status, and subsequently the two taxa have been confirmed as distinct species by genetic analyses [K.A. Hayes, R.C. Joshi, S.C. Thiengo and R.H. Cowie, in prep.].

Map of Pomacea diffusa habitat

Pomacea diffusa Mating | Depositing Egg Clutches

Predation On Pomacea diffusa

Pomacea diffusa Blume, 1957 Living Animal

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