Crisanto Gómez - Academia.edu (original) (raw)
Papers by Crisanto Gómez
research funders in the common goal of maximizing access to critical research.
This study is focused on the dominance exerted by the invasive Argentine ant over native ants in ... more This study is focused on the dominance exerted by the invasive Argentine ant over native ants in a coastal Mediterranean area. The impact of this invasive ant on native ant assemblages and its conse-quences on total ant biomass and on the intensity of habitat exploration were evaluated. Foraging ants were observed and their trajectories recorded during 5-minute periods in two study zones, one invaded and the other non-invaded. Ant species detected, ant worker abundance, ant biomass and the intensity of soil surface searching done by ants were compared between the two zones. The Argentine ant invasion provoked a drastic reduction of the ant species richness. Apparently only one native ant species is able to coexist with the Argentine ant, the cryptic Plagiolepis pygmaea. Ant worker abundance was also modified after the invasion: the number of Argentine ant workers detected, which represented 92 % of the invaded zone, was two times higher than the
Norwegian journal of entomology, 2005
65 The Argentine ant, Linepithema humile (Mayr,1868b) was found in two fl ats above a stable at R... more 65 The Argentine ant, Linepithema humile (Mayr,1868b) was found in two fl ats above a stable at RY: Sandnes (58.85oN; 5.73oE)). The ants were fi rst seen in November 2004, but not identifi ed to species before February 2005 when a pest control company was engaged to eradicate the pest. According to the pest controller, several hundred workers were present. However, no brood, queens or males were found. The owners of the fl ats had recently been visiting Italy and Spain with their horses and the ants had also been observed in the trailer transporting the horses on return to Norway.
espanolSe presentan los resultados de la interaccion de la hormiga Pheidole pallidula (Nyl.) con ... more espanolSe presentan los resultados de la interaccion de la hormiga Pheidole pallidula (Nyl.) con semillas de varias especies de euforbiaceas en lugares donde coexisten ambas y la respuesta de diferentes poblaciones de P. pallidula frente a semillas de una de las especies estudiadas, E. characias. Hormigas mantenidas en nidos artificiales en laboratorio no consumieron semillas de E. characias, E. serrata y E. nicaeensis durante un periodo de observacion de dos meses. Pheidole pallidula se comporta como dispersante de E. characias, E. serrata serrata, E. serrata phylloclada, E. nicaeensis y E. biumbellata. Las pequenas semillas de E. helioscopia (longitud 1.73 mm) provocan una respuesta de transporte en P. pallidula menor; en este caso la posibilidad de granivoria no puede ser rechazada catalaEs presenten els resultats de la interaccio de la formiga Pheidole pallidula (Nyl.) amb granes de diferents especies de lleterasses en llocs on coexisteixen totes dues i la resposta de diferents ...
A B S T R A C T. ‐ The effect of A rgentine ant (Linepithema humile) invasion on the dispersal pr... more A B S T R A C T. ‐ The effect of A rgentine ant (Linepithema humile) invasion on the dispersal predation balance of non-myrmecochorous seeds by ants and vertebrates is analyzed. T h r e e Papilionaceae, Calicotome spinosa, Psoralea bituminosa, and S p a rtium junceum, were studied. The seeds were made available in field trials during 48 hour periods using ant and vertebrate exclusions in zones invaded by L. humile and non-invaded zones. The A rgentine ant invasion resulted in the displacement of most of the native ant species, including the single seed predator ant in the non-invaded zone, Messor bouvieri. C o n s e q u e n t l y, the level of seed removal by ants was lower in the invaded zone for the three seed species. This could produce two opposite e ffects for the plant: a positive reduction of seed predation and a negative loss of seed dispersal due to diszoochory (the seed dispersal performed by seed eating ants). The three studied species s u ffered different intensities of ...
La macroecologie, l'etude de la repartition de l'espace physique et des ressources ecolog... more La macroecologie, l'etude de la repartition de l'espace physique et des ressources ecologiques parmi les especes, tente de demontrer des patterns dans certains traits specifiques a des echelles spatiales assez larges. Un trait specifique tres important est la taille corporelle. Pour caracteriser la distribution specifique de la masse corporelle, le parametre utilise pour les donnees individuelles est la moyenne des variables representant la taille (longueur du corps, masse, longueur de l'aile anterieure, envergure des ailes, longueur du cephalothorax, selon les differents groupes). Chez les especes de Fourmis iberiques ayant des ouvrieres, une proportion non negligeable (21%) montre un degre de polymorphisme. Ce fait est du a la presence d'especes polymorphes et d'especes monomorphes qui presentent une forte variation. Pour controler l'importance de cette variation corporelle nous avons etudie l'influence sur la distribution specifique de la masse corpore...
Ecology, Jan 16, 2016
What forces structure ecological assemblages? A key limitation to general insights about assembla... more What forces structure ecological assemblages? A key limitation to general insights about assemblage structure is the availability of data that are collected at a small spatial grain (local assemblages) and a large spatial extent (global coverage). Here, we present published and unpublished data from 51,388 ant abundance and occurrence records of more than 2693 species and 7953 morphospecies from local assemblages collected at 4212 locations around the world. Ants were selected because they are diverse and abundant globally, comprise a large fraction of animal biomass in most terrestrial communities, and are key contributors to a range of ecosystem functions. Data were collected between 1949 and 2014, and include, for each geo-referenced sampling site, both the identity of the ants collected and details of sampling design, habitat type and degree of disturbance. The aim of compiling this dataset was to provide comprehensive species abundance data in order to test relationships betwee...
Naturwissenschaften, 2008
Harvester ants have traditionally been considered as seed predators that negatively affect plants... more Harvester ants have traditionally been considered as seed predators that negatively affect plants. In some cases, however, they can also act as positive seed dispersers. During field observations, we noted that a portion of Psoralea bituminosa seeds that were ...
Journal of Biogeography, 1998
... important to note that published studies from the Southern hemisphere-seven to our knowledge-... more ... important to note that published studies from the Southern hemisphere-seven to our knowledge-that evaluate distances and dispersal curves have been made in sclerophyllous vegetation whereas studies from the Northern hemisphere-sixteen to our knowledge-have been ...
PLOS ONE
In insect societies, chemical communication plays an important role in colony reproduction and in... more In insect societies, chemical communication plays an important role in colony reproduction and individual social status. Many studies have indicated that cuticular hydrocarbons (CHCs) are the main chemical compounds encoding reproductive status. However, these studies have largely focused on queenless or monogynous species whose workers are capable of egg laying and have mainly explored the mechanisms underlying queen-worker or worker-worker reproductive conflicts. Less is known about what occurs in highly polygynous ant species with permanently sterile workers. Here, we used the Argentine ant as a model to examine the role of CHCs in communicating reproductive information in such insect societies. The Argentine ant is unicolonial, highly polygynous, and polydomous. We identified several CHCs whose presence and levels were correlated with queen age, reproductive status, and fertility. Our results also provide new insights into queen executions in the Argentine ant, a distinctive feature displayed by this species in its introduced range. Each spring, just before new sexuals appear, workers eliminate up to 90% of the mated queens in their colonies. We discovered that queens that survived execution had different CHC profiles from queens present before and during execution. More specifically, levels of some CHCs were higher in the survivors, suggesting that workers could eliminate queens based on their chemical profiles. In addition, queen CHC profiles differed based on season and species range (native vs. introduced). Overall, the results of this study provide new evidence that CHCs serve as queen signals and do more than just regulate worker reproduction.
Global change biology, Oct 30, 2018
The relationship between levels of dominance and species richness is highly contentious, especial... more The relationship between levels of dominance and species richness is highly contentious, especially in ant communities. The dominance-impoverishment rule states that high levels of dominance only occur in species-poor communities, but there appear to be many cases of high levels of dominance in highly diverse communities. The extent to which dominant species limit local richness through competitive exclusion remains unclear, but such exclusion appears more apparent for non-native rather than native dominant species. Here we perform the first global analysis of the relationship between behavioral dominance and species richness. We used data from 1,293 local assemblages of ground-dwelling ants distributed across five continents to document the generality of the dominance-impoverishment rule, and to identify the biotic and abiotic conditions under which it does and does not apply. We found that the behavioral dominance-diversity relationship varies greatly, and depends on whether domin...
After most of the native ant species are displaced by the Argentine ant invasion, it is probable ... more After most of the native ant species are displaced by the Argentine ant invasion, it is probable that some ecological processes carried out by natives are not replaced. In some cases this could be due to a morphological difference between the Argentine ant and the displaced native ants. The significant decrease in ant richness after the invasion (only two species detected in the invaded zones vs. 25 species in surrounding non-invaded zones) implies a drastic reduction in the ant mandible gap range (the mandible gap spectra of all the ant species in a community) in the invaded zones. This reduction could explain why some roles that were previously carried out by the displaced native species are not performed by the invasive species. This could be due to a functional inability to carry out these activities. The mandible gap was positively correlated with the ant body mass in the 26 ant species considered. The functional inability hypothesis could be applied to other invasive ants as well as to the Argentine ant.
ABSTRACr. Physics and biology in the dispersal of Euphorbia characias lo (Euphorbiaceae). Seed di... more ABSTRACr. Physics and biology in the dispersal of Euphorbia characias lo (Euphorbiaceae). Seed dispersal and establishment of Euphorbia characias in an abandoned field takes places in two steps. At first, seeds are ballistically ejected and distances attained are influenced by the height of the inflorencence and by the angle ofaxis of mature capsules. Seed weight, capsule orientation and force of dehiscence do not seem to intervene in that distance. When the seeds are scattered singly on top of soil some ant species retrieve them. Messor barbarus, a granivore, is a seed predator. Aphaenogaster senilis may be intepreted as a parasite of an eventual mutualism since the seeds taken by this species are deprived of the elaiosome and left outside, at the midden or farther away from the nest. Pheidole pallidula takes seeds to the nest, eats the elaiosome and leaves the seeds inside the nest, made in open field; seeds may germinate but do not establish because are eaten or die during winter. Tapinoma nigerrimum makes nests both in open field and under several plants (temporal nests). Only one of those plants, Inula viscosa (L.), that retains woody structu res during winter allows the establishment of seedlings emerging under its protection. ©Consorci Parc de Collserola
Es descriu el procés d'obertura dels endocarpis i l'alliberament de les llavors en Rhamnus alater... more Es descriu el procés d'obertura dels endocarpis i l'alliberament de les llavors en Rhamnus alaternus, i es determina si s'origina un despla~ament de llavors des dels punts d'origen. Igualment es contrasten aquests resultats amb el que succeeix en Rhamnus ludovici-salvatoris. En assecar-se l'item (endocarpi + llavor) s'origina una obertura majoritiria dels endocarpis (90% dels casos), que expulsen les llavors a distancies curtes (mitjanes.e.=3,70+5,96 cm) perb que arriben fins als 0,s metres. Aquestes distancies són majors que les aconseguides quan els items estan fixats (mitjanes. e.= 1.27k1.22 cm) (ex. femta &un vertebrat). Les disthncies que s'originen en R. ludovici-salvatoris són fins a sis vegades més curtes (mitjanes. e.= 0,61c2,87 cm). El mecanisme té tres conseqütncies: allunyar les llavors del punt d'origen, deixar-les disponibles a diferents organismes que podrien de nou remoure-les (ex. formigues i10 rosegadors) i afavorir l'emergtncia de plhntules. RESUMEN Se describe el proceso de apertura de 10s endocarpos y la liberación de las semillas en Rhamnus alaternus, y se determina si se origina un desplazamiento de las semillas desde 10s puntos de origen. Igualmente se contrastan estos resultados con 10 que se da en Rhamnus ludovicisalvatoris. Cuando se seca el item (endocarpo + semilla) se origina una apertura mayoritaria de 10s endocarpos (90% de 10s casos) expulsando las semillas a distancias cortas (mediaks. e.=3.70+5.96 cm) pero llegando hasta 10s 0,s metros. Estas distancias son mayores que cuando 10s items están pegados a un substrat0 (medies. e.= 1,27k1,22 cm) (ej. excremento de vertebrado). Las distancias que se originan en R. ludovici-salvatoris son hasta seis veces menores (mediaks. e.= 0,61*2,87 cm). El mecanisrno tiene tres consecuencias: alejar las semillas del punto de origen, dejarlas disponibles a diferentes organismos que podrían de nuevo removerlas (ej. hormigas ylo roedores) y favorecer la emergencia de plántulas. ABSTRA CT Endocarp opening and seed expulsion mechanism in evergreen buckthorn (Rhamnus alaternus L.) This paper presents a description of endocarp opening and seed release in Rhamnus alaternus. The seed movement from the original situation is studied and the results are compared with another species of this genus: Rhamnus ludovici-salvatoris. When the item (seed + endocarp) becomes dry a gap appears on the endocarp (90% of cases) which expels the seeds to short distances (mean+s.e.=3.70+5.96 cm; range=O-52.1 cm). Distances are greater when the items are attached (vertebrate faeces). The R. alaternus distances generated are six times greater than the R. ludovici-salvatoris distances. The mechanism generates 3 outcomes: seed removal from the original situation, supply of seeds for animals that can remove the seeds (ants and rodents) and contribution to the seedling emergence.
Fecha de aceptación de la nota: 20-12-02 RESUMEN: Se caracterizan, morfológica y estructuralmente... more Fecha de aceptación de la nota: 20-12-02 RESUMEN: Se caracterizan, morfológica y estructuralmente, los frutos y semillas de Rhamnus alaternus. Los frutos del aladierno presentan alta variabilidad en volumen (media ± s.e. = 192,77 ± 47,21 mm 3) y peso (240,15 ± 59,14 mg), siendo la pulpa el mayor porcentaje en referencia al volumen y peso fresco. El resto del fruto corresponde a endocarpos y semillas, los cuales suponen globalmente el 19% del peso total del fruto. El número de endocarpos fluctúa entre 2 y 5, presentando una media de 3,10 ± 0,09 endocarpos/fruto. Cada endocarpo suele presentar una semilla desarrollada en su interior (95% de los casos) originando una media de 2,93 ± 0,03 semillas por fruto. Existe mayor viabilidad en las semillas procedentes de endocarpos abiertos que en las procedentes de endocarpos cerrados. Las semillas presentan un eleosoma que representa el 4,05% del peso de la semilla. Las características de las diásporas tendrán influencia en la biología dispersiva de esta especie: frutos carnosos atractivos para vertebrados frugívoros y semillas con eleosoma atractivos a hormigas.
Resumen: Se ofrecen datos de 22 especies recolectadas mediante trampas de caída en suelo de pinar... more Resumen: Se ofrecen datos de 22 especies recolectadas mediante trampas de caída en suelo de pinares, durante los meses de juniojulio del año 2011, en el bosque de Mohago (Olmedo, Valladolid, España). Todas ellas resultan novedosas en el marco provincial, por ser Valladolid una de las provincias más ignoradas desde la perspectiva faunística. Se propone una nueva sinonimia: Nomisia fagei Dalmas, 1921 syn. n. de Nomisia excerpta (O. P.-Cambridge, 1872) y se amplía el área de distribución conocida en la Península de Berlandina plumalis (O. P.-Cambridge, 1872), Poecilochroa albomaculata (Lucas, 18446) y Philodromus fuscomarginatus (De Geer,
research funders in the common goal of maximizing access to critical research.
This study is focused on the dominance exerted by the invasive Argentine ant over native ants in ... more This study is focused on the dominance exerted by the invasive Argentine ant over native ants in a coastal Mediterranean area. The impact of this invasive ant on native ant assemblages and its conse-quences on total ant biomass and on the intensity of habitat exploration were evaluated. Foraging ants were observed and their trajectories recorded during 5-minute periods in two study zones, one invaded and the other non-invaded. Ant species detected, ant worker abundance, ant biomass and the intensity of soil surface searching done by ants were compared between the two zones. The Argentine ant invasion provoked a drastic reduction of the ant species richness. Apparently only one native ant species is able to coexist with the Argentine ant, the cryptic Plagiolepis pygmaea. Ant worker abundance was also modified after the invasion: the number of Argentine ant workers detected, which represented 92 % of the invaded zone, was two times higher than the
Norwegian journal of entomology, 2005
65 The Argentine ant, Linepithema humile (Mayr,1868b) was found in two fl ats above a stable at R... more 65 The Argentine ant, Linepithema humile (Mayr,1868b) was found in two fl ats above a stable at RY: Sandnes (58.85oN; 5.73oE)). The ants were fi rst seen in November 2004, but not identifi ed to species before February 2005 when a pest control company was engaged to eradicate the pest. According to the pest controller, several hundred workers were present. However, no brood, queens or males were found. The owners of the fl ats had recently been visiting Italy and Spain with their horses and the ants had also been observed in the trailer transporting the horses on return to Norway.
espanolSe presentan los resultados de la interaccion de la hormiga Pheidole pallidula (Nyl.) con ... more espanolSe presentan los resultados de la interaccion de la hormiga Pheidole pallidula (Nyl.) con semillas de varias especies de euforbiaceas en lugares donde coexisten ambas y la respuesta de diferentes poblaciones de P. pallidula frente a semillas de una de las especies estudiadas, E. characias. Hormigas mantenidas en nidos artificiales en laboratorio no consumieron semillas de E. characias, E. serrata y E. nicaeensis durante un periodo de observacion de dos meses. Pheidole pallidula se comporta como dispersante de E. characias, E. serrata serrata, E. serrata phylloclada, E. nicaeensis y E. biumbellata. Las pequenas semillas de E. helioscopia (longitud 1.73 mm) provocan una respuesta de transporte en P. pallidula menor; en este caso la posibilidad de granivoria no puede ser rechazada catalaEs presenten els resultats de la interaccio de la formiga Pheidole pallidula (Nyl.) amb granes de diferents especies de lleterasses en llocs on coexisteixen totes dues i la resposta de diferents ...
A B S T R A C T. ‐ The effect of A rgentine ant (Linepithema humile) invasion on the dispersal pr... more A B S T R A C T. ‐ The effect of A rgentine ant (Linepithema humile) invasion on the dispersal predation balance of non-myrmecochorous seeds by ants and vertebrates is analyzed. T h r e e Papilionaceae, Calicotome spinosa, Psoralea bituminosa, and S p a rtium junceum, were studied. The seeds were made available in field trials during 48 hour periods using ant and vertebrate exclusions in zones invaded by L. humile and non-invaded zones. The A rgentine ant invasion resulted in the displacement of most of the native ant species, including the single seed predator ant in the non-invaded zone, Messor bouvieri. C o n s e q u e n t l y, the level of seed removal by ants was lower in the invaded zone for the three seed species. This could produce two opposite e ffects for the plant: a positive reduction of seed predation and a negative loss of seed dispersal due to diszoochory (the seed dispersal performed by seed eating ants). The three studied species s u ffered different intensities of ...
La macroecologie, l'etude de la repartition de l'espace physique et des ressources ecolog... more La macroecologie, l'etude de la repartition de l'espace physique et des ressources ecologiques parmi les especes, tente de demontrer des patterns dans certains traits specifiques a des echelles spatiales assez larges. Un trait specifique tres important est la taille corporelle. Pour caracteriser la distribution specifique de la masse corporelle, le parametre utilise pour les donnees individuelles est la moyenne des variables representant la taille (longueur du corps, masse, longueur de l'aile anterieure, envergure des ailes, longueur du cephalothorax, selon les differents groupes). Chez les especes de Fourmis iberiques ayant des ouvrieres, une proportion non negligeable (21%) montre un degre de polymorphisme. Ce fait est du a la presence d'especes polymorphes et d'especes monomorphes qui presentent une forte variation. Pour controler l'importance de cette variation corporelle nous avons etudie l'influence sur la distribution specifique de la masse corpore...
Ecology, Jan 16, 2016
What forces structure ecological assemblages? A key limitation to general insights about assembla... more What forces structure ecological assemblages? A key limitation to general insights about assemblage structure is the availability of data that are collected at a small spatial grain (local assemblages) and a large spatial extent (global coverage). Here, we present published and unpublished data from 51,388 ant abundance and occurrence records of more than 2693 species and 7953 morphospecies from local assemblages collected at 4212 locations around the world. Ants were selected because they are diverse and abundant globally, comprise a large fraction of animal biomass in most terrestrial communities, and are key contributors to a range of ecosystem functions. Data were collected between 1949 and 2014, and include, for each geo-referenced sampling site, both the identity of the ants collected and details of sampling design, habitat type and degree of disturbance. The aim of compiling this dataset was to provide comprehensive species abundance data in order to test relationships betwee...
Naturwissenschaften, 2008
Harvester ants have traditionally been considered as seed predators that negatively affect plants... more Harvester ants have traditionally been considered as seed predators that negatively affect plants. In some cases, however, they can also act as positive seed dispersers. During field observations, we noted that a portion of Psoralea bituminosa seeds that were ...
Journal of Biogeography, 1998
... important to note that published studies from the Southern hemisphere-seven to our knowledge-... more ... important to note that published studies from the Southern hemisphere-seven to our knowledge-that evaluate distances and dispersal curves have been made in sclerophyllous vegetation whereas studies from the Northern hemisphere-sixteen to our knowledge-have been ...
PLOS ONE
In insect societies, chemical communication plays an important role in colony reproduction and in... more In insect societies, chemical communication plays an important role in colony reproduction and individual social status. Many studies have indicated that cuticular hydrocarbons (CHCs) are the main chemical compounds encoding reproductive status. However, these studies have largely focused on queenless or monogynous species whose workers are capable of egg laying and have mainly explored the mechanisms underlying queen-worker or worker-worker reproductive conflicts. Less is known about what occurs in highly polygynous ant species with permanently sterile workers. Here, we used the Argentine ant as a model to examine the role of CHCs in communicating reproductive information in such insect societies. The Argentine ant is unicolonial, highly polygynous, and polydomous. We identified several CHCs whose presence and levels were correlated with queen age, reproductive status, and fertility. Our results also provide new insights into queen executions in the Argentine ant, a distinctive feature displayed by this species in its introduced range. Each spring, just before new sexuals appear, workers eliminate up to 90% of the mated queens in their colonies. We discovered that queens that survived execution had different CHC profiles from queens present before and during execution. More specifically, levels of some CHCs were higher in the survivors, suggesting that workers could eliminate queens based on their chemical profiles. In addition, queen CHC profiles differed based on season and species range (native vs. introduced). Overall, the results of this study provide new evidence that CHCs serve as queen signals and do more than just regulate worker reproduction.
Global change biology, Oct 30, 2018
The relationship between levels of dominance and species richness is highly contentious, especial... more The relationship between levels of dominance and species richness is highly contentious, especially in ant communities. The dominance-impoverishment rule states that high levels of dominance only occur in species-poor communities, but there appear to be many cases of high levels of dominance in highly diverse communities. The extent to which dominant species limit local richness through competitive exclusion remains unclear, but such exclusion appears more apparent for non-native rather than native dominant species. Here we perform the first global analysis of the relationship between behavioral dominance and species richness. We used data from 1,293 local assemblages of ground-dwelling ants distributed across five continents to document the generality of the dominance-impoverishment rule, and to identify the biotic and abiotic conditions under which it does and does not apply. We found that the behavioral dominance-diversity relationship varies greatly, and depends on whether domin...
After most of the native ant species are displaced by the Argentine ant invasion, it is probable ... more After most of the native ant species are displaced by the Argentine ant invasion, it is probable that some ecological processes carried out by natives are not replaced. In some cases this could be due to a morphological difference between the Argentine ant and the displaced native ants. The significant decrease in ant richness after the invasion (only two species detected in the invaded zones vs. 25 species in surrounding non-invaded zones) implies a drastic reduction in the ant mandible gap range (the mandible gap spectra of all the ant species in a community) in the invaded zones. This reduction could explain why some roles that were previously carried out by the displaced native species are not performed by the invasive species. This could be due to a functional inability to carry out these activities. The mandible gap was positively correlated with the ant body mass in the 26 ant species considered. The functional inability hypothesis could be applied to other invasive ants as well as to the Argentine ant.
ABSTRACr. Physics and biology in the dispersal of Euphorbia characias lo (Euphorbiaceae). Seed di... more ABSTRACr. Physics and biology in the dispersal of Euphorbia characias lo (Euphorbiaceae). Seed dispersal and establishment of Euphorbia characias in an abandoned field takes places in two steps. At first, seeds are ballistically ejected and distances attained are influenced by the height of the inflorencence and by the angle ofaxis of mature capsules. Seed weight, capsule orientation and force of dehiscence do not seem to intervene in that distance. When the seeds are scattered singly on top of soil some ant species retrieve them. Messor barbarus, a granivore, is a seed predator. Aphaenogaster senilis may be intepreted as a parasite of an eventual mutualism since the seeds taken by this species are deprived of the elaiosome and left outside, at the midden or farther away from the nest. Pheidole pallidula takes seeds to the nest, eats the elaiosome and leaves the seeds inside the nest, made in open field; seeds may germinate but do not establish because are eaten or die during winter. Tapinoma nigerrimum makes nests both in open field and under several plants (temporal nests). Only one of those plants, Inula viscosa (L.), that retains woody structu res during winter allows the establishment of seedlings emerging under its protection. ©Consorci Parc de Collserola
Es descriu el procés d'obertura dels endocarpis i l'alliberament de les llavors en Rhamnus alater... more Es descriu el procés d'obertura dels endocarpis i l'alliberament de les llavors en Rhamnus alaternus, i es determina si s'origina un despla~ament de llavors des dels punts d'origen. Igualment es contrasten aquests resultats amb el que succeeix en Rhamnus ludovici-salvatoris. En assecar-se l'item (endocarpi + llavor) s'origina una obertura majoritiria dels endocarpis (90% dels casos), que expulsen les llavors a distancies curtes (mitjanes.e.=3,70+5,96 cm) perb que arriben fins als 0,s metres. Aquestes distancies són majors que les aconseguides quan els items estan fixats (mitjanes. e.= 1.27k1.22 cm) (ex. femta &un vertebrat). Les disthncies que s'originen en R. ludovici-salvatoris són fins a sis vegades més curtes (mitjanes. e.= 0,61c2,87 cm). El mecanisme té tres conseqütncies: allunyar les llavors del punt d'origen, deixar-les disponibles a diferents organismes que podrien de nou remoure-les (ex. formigues i10 rosegadors) i afavorir l'emergtncia de plhntules. RESUMEN Se describe el proceso de apertura de 10s endocarpos y la liberación de las semillas en Rhamnus alaternus, y se determina si se origina un desplazamiento de las semillas desde 10s puntos de origen. Igualmente se contrastan estos resultados con 10 que se da en Rhamnus ludovicisalvatoris. Cuando se seca el item (endocarpo + semilla) se origina una apertura mayoritaria de 10s endocarpos (90% de 10s casos) expulsando las semillas a distancias cortas (mediaks. e.=3.70+5.96 cm) pero llegando hasta 10s 0,s metros. Estas distancias son mayores que cuando 10s items están pegados a un substrat0 (medies. e.= 1,27k1,22 cm) (ej. excremento de vertebrado). Las distancias que se originan en R. ludovici-salvatoris son hasta seis veces menores (mediaks. e.= 0,61*2,87 cm). El mecanisrno tiene tres consecuencias: alejar las semillas del punto de origen, dejarlas disponibles a diferentes organismos que podrían de nuevo removerlas (ej. hormigas ylo roedores) y favorecer la emergencia de plántulas. ABSTRA CT Endocarp opening and seed expulsion mechanism in evergreen buckthorn (Rhamnus alaternus L.) This paper presents a description of endocarp opening and seed release in Rhamnus alaternus. The seed movement from the original situation is studied and the results are compared with another species of this genus: Rhamnus ludovici-salvatoris. When the item (seed + endocarp) becomes dry a gap appears on the endocarp (90% of cases) which expels the seeds to short distances (mean+s.e.=3.70+5.96 cm; range=O-52.1 cm). Distances are greater when the items are attached (vertebrate faeces). The R. alaternus distances generated are six times greater than the R. ludovici-salvatoris distances. The mechanism generates 3 outcomes: seed removal from the original situation, supply of seeds for animals that can remove the seeds (ants and rodents) and contribution to the seedling emergence.
Fecha de aceptación de la nota: 20-12-02 RESUMEN: Se caracterizan, morfológica y estructuralmente... more Fecha de aceptación de la nota: 20-12-02 RESUMEN: Se caracterizan, morfológica y estructuralmente, los frutos y semillas de Rhamnus alaternus. Los frutos del aladierno presentan alta variabilidad en volumen (media ± s.e. = 192,77 ± 47,21 mm 3) y peso (240,15 ± 59,14 mg), siendo la pulpa el mayor porcentaje en referencia al volumen y peso fresco. El resto del fruto corresponde a endocarpos y semillas, los cuales suponen globalmente el 19% del peso total del fruto. El número de endocarpos fluctúa entre 2 y 5, presentando una media de 3,10 ± 0,09 endocarpos/fruto. Cada endocarpo suele presentar una semilla desarrollada en su interior (95% de los casos) originando una media de 2,93 ± 0,03 semillas por fruto. Existe mayor viabilidad en las semillas procedentes de endocarpos abiertos que en las procedentes de endocarpos cerrados. Las semillas presentan un eleosoma que representa el 4,05% del peso de la semilla. Las características de las diásporas tendrán influencia en la biología dispersiva de esta especie: frutos carnosos atractivos para vertebrados frugívoros y semillas con eleosoma atractivos a hormigas.
Resumen: Se ofrecen datos de 22 especies recolectadas mediante trampas de caída en suelo de pinar... more Resumen: Se ofrecen datos de 22 especies recolectadas mediante trampas de caída en suelo de pinares, durante los meses de juniojulio del año 2011, en el bosque de Mohago (Olmedo, Valladolid, España). Todas ellas resultan novedosas en el marco provincial, por ser Valladolid una de las provincias más ignoradas desde la perspectiva faunística. Se propone una nueva sinonimia: Nomisia fagei Dalmas, 1921 syn. n. de Nomisia excerpta (O. P.-Cambridge, 1872) y se amplía el área de distribución conocida en la Península de Berlandina plumalis (O. P.-Cambridge, 1872), Poecilochroa albomaculata (Lucas, 18446) y Philodromus fuscomarginatus (De Geer,