Marcela Castelo | Universidad de Buenos Aires (original) (raw)

Papers by Marcela Castelo

Acta Zoologica Lilloana, 2018

Ecological Entomology, Nov 16, 2021

Frontiers in agronomy, Jan 27, 2023

Journal of Insect Physiology, 2004

The robber fly Mallophora ruficauda is the most important pest of apiculture in the Pampas region... more The robber fly Mallophora ruficauda is the most important pest of apiculture in the Pampas region of Argentina. Adults prey on honeybees and other insects, while larvae parasitize larvae of scarab beetles, which live underground. Females of M. ruficauda do not search for hosts but instead lay eggs in tall pastures. Once hatched, larvae drop to the ground and burrow underground to search for their hosts. We tested in the laboratory whether larvae of M. ruficauda actively search for their hosts using host and/or host-related chemical cues. We report that M. ruficauda detects its host using chemical cues that originate in the posterior half of the host's body, most likely from an abdominal exocrine structure. This particular host-searching strategy is described for the first time in Asilidae.

The Strange‐tailed Tyrant (Alectrurus risora) is an insectivorous flycatcher (Tyrannidae) endemic... more The Strange‐tailed Tyrant (Alectrurus risora) is an insectivorous flycatcher (Tyrannidae) endemic to the natural tall grasslands of northern Argentina and southern Paraguay. Alectrurus risora has a polygynous mating system and the abundance of arthropods could be a major factor determining the establishment of male breeding territories and the extent of the breeding season, which is shorter than in most other reported tyrant flycatchers. To investigate this hypothesis, we examined the abundance of arthropods in upland and lowland breeding habitats. Upland habitats seem to be preferred for breeding, and usually harbour more nests. Data from one year showed that, for both grasslands, the beginning of the breeding season coincides with a greater availability of arthropods, and that the short reproductive season of A. risora coincides with a general lower availability of prey during February and March in the year we conducted the study. In upland territories, males attracted more female...

Bulletin of Entomological Research, 2015

The robber flyMallophora ruficaudais one of the most important apicultural pests in the Pampas re... more The robber flyMallophora ruficaudais one of the most important apicultural pests in the Pampas region of Argentina. This species is a parasitoid of scarab beetle larvae. Females lay eggs away from the host, and the larvae perform active search behaviour towardCyclocephala signaticollisthird instar larvae, parasitoid's preferred host. This behaviour is mediated by host-related chemical cues produced in hosts’ fermentation chamber. Also,C. signaticollislarvae are attracted to fermentation chamber extracts. As scarab larvae have microbe-rich fermentation chamber, it has been suggested that microorganisms could be involved in the production of these semiochemicals. The aims of this work were first to ascertain the presence of microorganisms in the fermentation chamber ofC. signaticollislarvae and second to determine the role of microorganisms in the orientation response of parasitoid and host larvae. We found that microorganisms-freeC. signaticollislarvae showed deterioration in the...

Biology, 2022

Parasitoids are organisms that kill their host before completing their development. Typical paras... more Parasitoids are organisms that kill their host before completing their development. Typical parasitoids belong to Hymenoptera, whose females search for the hosts. But some atypical Diptera parasitoids also have searching larvae that must orientate toward, encounter, and accept hosts, through cues with different levels of detectability. In this work, the chemical cues involved in the detection of the host by parasitoid larvae of the genus Mallophora are shown with a behavioral approach. Through olfactometry assays, we show that two species of Mallophora orient to different host species and that chemical cues are produced by microorganisms. We also show that treating potential hosts with antibiotics reduces attractiveness on M. ruficauda but not to M. bigoti suggesting that endosymbiotic bacteria responsible for the host cues production should be located in different parts of the host. In fact, we were able to show that M. bigoti is attracted to frass from the most common host. Additi...

Bulletin of Entomological Research, 2017

Changes in environmental conditions influence the performance of organisms in every aspect of the... more Changes in environmental conditions influence the performance of organisms in every aspect of their life. Being capable of accurately sensing these changes allow organisms to better adapt. The detection of environmental conditions involves different sensory modalities. There are many studies on the morphology of different sensory structures but not so many studies showing their function. Here we studied the morphology of different sensory structures in the larva of a dipteran parasitoid. We occluded the putative sensory structures coupling the morphology with their function. First, we could develop a non-invasive method in which we occluded the putative sensorial structures annulling their function temporarily. Regarding their functionality, we found that larvae of Mallophora ruficauda require simultaneously of the sensilla found both in the antennae and those of the maxillary palps in order to orient to its host. When either both antennae or both maxillary palps were occluded, no o...

Zoomorphology, 2013

ABSTRACT The robber fly Mallophora ruficauda is a parasitoid of white grubs (Coleoptera: Scarabae... more ABSTRACT The robber fly Mallophora ruficauda is a parasitoid of white grubs (Coleoptera: Scarabaeidae) inhabiting in Pampa’s region of Argentina. Females locate host’s habitat and lay eggs away from the host in tall grasses. After hatching, larvae fall to the ground and actively seek hosts. Previous works suggested that female would detect the presence of host’s chemical cues, but sensory organs involved in olfaction are still unknown. However, few studies have looked at dipteran parasitoids’ sensilla and no study has been undertaken in Asilidae species. The aim of this work was to determine the presence, density, distribution and morphology of chemosensilla in M. ruficauda antennae using optic and scanning microscope techniques. We found that antennae have 4 segments: scape, pedicel, postpedicel and style. We identified basiconic and trichoidea sensilla, small and long bristles, and sensory pits. Basiconic sensilla are multiporous and are widely spread between the small bristles through the postpedicel. Tricoid sensilla are grouped in 6-8 units on latero-ventral margin of postpedicel, have mobile base, striated wall and an apical porous. Small bristles are present in the pedicel and postpedicel and long bristles are found in groups on scape and pedicel. Three different types of sensory pits were observed, with basiconic sensilla, distributed along external and internal lateral side of the postpedicel. Considering the morphological characteristics of the antennae, and based on the olfaction biomechanics, the structure and distribution of these cuticular structures of the parasitoid antennae would contribute to the odour detection mechanism in adults of M. ruficauda.

Journal of Insect Physiology, Apr 30, 2004

The robber fly Mallophora ruficauda is the most important pest of apiculture in the Pampas region... more The robber fly Mallophora ruficauda is the most important pest of apiculture in the Pampas region of Argentina. Adults prey on honeybees and other insects, while larvae parasitize larvae of scarab beetles, which live underground. Females of M. ruficauda do not search for hosts but instead lay eggs in tall pastures. Once hatched, larvae drop to the ground and burrow underground to search for their hosts. We tested in the laboratory whether larvae of M. ruficauda actively search for their hosts using host and/or host-related chemical cues. We report that M. ruficauda detects its host using chemical cues that originate in the posterior half of the host's body, most likely from an abdominal exocrine structure. This particular host-searching strategy is described for the first time in Asilidae.

The robber fly Mallophora ruficauda is one of the principal pests of apiculture in the Pampas reg... more The robber fly Mallophora ruficauda is one of the principal pests of apiculture in the Pampas region of Argentina. As adults they prey on honey bees and other insects, while as larvae they are solitary ectoparasitoids of third instar scarab beetle larvae. Females of M. ruficauda lay eggs away from the host in tall grasses. After being dispersed by the wind, larvae drop to the ground, where they dig in search of their hosts. It is known that second instar larvae of M. ruficauda exhibit active host searching behaviour towards its preferred host, third instar larva of Cyclocephala signaticollis. Although the means by which host location occurs has been studied and since superparasitism is a frequent scenario in the field, no information about host discrimination and host acceptance is available. We carried out studies in the field and behavioural experiments in the laboratory to determine if M. ruficauda is capable of quality host discrimination. We also studied if this parasitoid is c...

The robber fly Mallophora ruficauda is one of the principal apiculture pests in the Pampas region... more The robber fly Mallophora ruficauda is one of the principal apiculture pests in the Pampas region of Argentina. As adults, they prey on honeybees and other insects, while as larvae they are ectoparasitoids of third-instar scarab larvae. Females of M. ruficauda lay eggs in tall grasses. After being dispersed by the wind, larvae drop to the ground, where they dig in search of their hosts. It is known that M. ruficauda larvae exhibit active host-searching behaviour; however, it is unknown which instars are involved in this search. We carried out experiments in the laboratory to determine which larval stages are involved in host location. We report here that the second instar of M. ruficauda orientates specifically toward a source of Cyclocephala signaticollis odour, while first larval instar is indifferent to the host cues. Furthermore, we have determined that second instar larvae are more motivated to initiate exploratory movements than larva of the first stage. So far as we know, thi...

Ornitologia Neotropical, 2016

∙ The Strange‐tailed Tyrant ( Alectrurus risora ) is an insectivorous flycatcher (Tyrannidae) end... more ∙ The Strange‐tailed Tyrant ( Alectrurus risora ) is an insectivorous flycatcher (Tyrannidae) endemic to the natural tall grasslands of northern Argentina and southern Paraguay. Alectrurus risora has a polygynous mating system and the abundance of arthropods could be a major factor determining the establishment of male breeding territories and the extent of the breeding season, which is shorter than in most other reported tyrant flycatchers. To investigate this hypothesis, we examined the abundance of arthropods in upland and lowland breeding habitats. Upland habitats seem to be preferred for breeding, and usually harbour more nests. Data from one year showed that, for both grasslands, the beginning of the breeding season coincides with a greater availability of arthropods, and that the short reproductive season of A. risora coincides with a general lower availability of prey during February and March in the year we conducted the study. In upland territories, males attracted more fe...

The robber fly Mallophora ruficauda Weidemann (Diptera: Asilidae) is an important pest of apicult... more The robber fly Mallophora ruficauda Weidemann (Diptera: Asilidae) is an important pest of apiculture in the Pampas of Argentina. As adults, they prey on honey bees and other insects, whereas the larvae are ectoparasitoids of Scarabaeidae grubs. Females of M. ruficauda lay eggs in grassland where the larvae drop to the ground after being wind-dispersed and burrow underground searching for their hosts. A temporal asynchrony exists between the appearance of the parasitoid larvae and the host, with the parasitoid appearing earlier than the host. The present study investigates whether a strategy of synchronization with the host exists in M. ruficauda and determines which of the larval instars are responsible for it. Survival patterns and duration of the immature stages of the parasitoid are investigated to determine whether there is a modulation in the development at any time that could reduce the asynchrony. Experiments are carried out to determine the survival and duration of free-livi...

The robber fly Mallophora ruficauda is one of the principal pests of apiculture in the Pampas reg... more The robber fly Mallophora ruficauda is one of the principal pests of apiculture in the Pampas region of Argentina. Larvae are solitary ectoparasitoids of third-instar scarab beetle larvae. Females of M. ruficauda do not lay eggs on or near the hosts, but on tall grasses. After hatching, larvae are dispersed by the wind and drop to the ground, where they dig and search for potential hosts. It is known that second-instar larvae of M. ruficauda exhibit active host-searching behaviour towards their preferred hosts, i.e., third-instar larvae of Cyclocephala signaticollis. Although host-location seems to be mediated by chemical cues, the mechanism of orientation and the sensory organs involved in host location remain unknown. We carried out behavioural experiments in the laboratory to address these questions. We also tested whether the orientation behaviour is exclusively based on the use of chemical cues. We found that larvae of M. ruficauda detect the chemicals with chemosensilla on the...

El moscardon cazador de abejas, Mallophora ruficauda, es la plaga de la apicultura mas importante... more El moscardon cazador de abejas, Mallophora ruficauda, es la plaga de la apicultura mas importante de la region pampeana argentina. Durante el estado adulto es depredador de insectos como las abejas meliferas y durante el estado larvario es parasitoide de larvas de Scarabaeidae, comunmente denominadas gusanos blancos del suelo. El objetivo de esta Tesis es estudiar aspectos basicos de la biologia y ecologia de esta especie, con especial enfasis en los mecanismos de localizacion y explotacion de sus hospedadores. Particularmente, se estudia cual es la contribucion relativa de las hembras y de las larvas en estos procesos y como son los patrones de parasitismo resultantes. Mallophora ruficauda deposita los huevos en ootecas, las cuales son puestas en vegetacion herbacea elevada y alambrados. Las hembras regulan el numero de huevos por ooteca en funcion de la altura de oviposicion en el sustrato, depositando mas cantidad de huevos a medida que se incrementa la altura. Ademas, selecciona...

Acta Zoologica Lilloana, 2018

Ecological Entomology, Nov 16, 2021

Frontiers in agronomy, Jan 27, 2023

Journal of Insect Physiology, 2004

The robber fly Mallophora ruficauda is the most important pest of apiculture in the Pampas region... more The robber fly Mallophora ruficauda is the most important pest of apiculture in the Pampas region of Argentina. Adults prey on honeybees and other insects, while larvae parasitize larvae of scarab beetles, which live underground. Females of M. ruficauda do not search for hosts but instead lay eggs in tall pastures. Once hatched, larvae drop to the ground and burrow underground to search for their hosts. We tested in the laboratory whether larvae of M. ruficauda actively search for their hosts using host and/or host-related chemical cues. We report that M. ruficauda detects its host using chemical cues that originate in the posterior half of the host's body, most likely from an abdominal exocrine structure. This particular host-searching strategy is described for the first time in Asilidae.

The Strange‐tailed Tyrant (Alectrurus risora) is an insectivorous flycatcher (Tyrannidae) endemic... more The Strange‐tailed Tyrant (Alectrurus risora) is an insectivorous flycatcher (Tyrannidae) endemic to the natural tall grasslands of northern Argentina and southern Paraguay. Alectrurus risora has a polygynous mating system and the abundance of arthropods could be a major factor determining the establishment of male breeding territories and the extent of the breeding season, which is shorter than in most other reported tyrant flycatchers. To investigate this hypothesis, we examined the abundance of arthropods in upland and lowland breeding habitats. Upland habitats seem to be preferred for breeding, and usually harbour more nests. Data from one year showed that, for both grasslands, the beginning of the breeding season coincides with a greater availability of arthropods, and that the short reproductive season of A. risora coincides with a general lower availability of prey during February and March in the year we conducted the study. In upland territories, males attracted more female...

Bulletin of Entomological Research, 2015

The robber flyMallophora ruficaudais one of the most important apicultural pests in the Pampas re... more The robber flyMallophora ruficaudais one of the most important apicultural pests in the Pampas region of Argentina. This species is a parasitoid of scarab beetle larvae. Females lay eggs away from the host, and the larvae perform active search behaviour towardCyclocephala signaticollisthird instar larvae, parasitoid's preferred host. This behaviour is mediated by host-related chemical cues produced in hosts’ fermentation chamber. Also,C. signaticollislarvae are attracted to fermentation chamber extracts. As scarab larvae have microbe-rich fermentation chamber, it has been suggested that microorganisms could be involved in the production of these semiochemicals. The aims of this work were first to ascertain the presence of microorganisms in the fermentation chamber ofC. signaticollislarvae and second to determine the role of microorganisms in the orientation response of parasitoid and host larvae. We found that microorganisms-freeC. signaticollislarvae showed deterioration in the...

Biology, 2022

Parasitoids are organisms that kill their host before completing their development. Typical paras... more Parasitoids are organisms that kill their host before completing their development. Typical parasitoids belong to Hymenoptera, whose females search for the hosts. But some atypical Diptera parasitoids also have searching larvae that must orientate toward, encounter, and accept hosts, through cues with different levels of detectability. In this work, the chemical cues involved in the detection of the host by parasitoid larvae of the genus Mallophora are shown with a behavioral approach. Through olfactometry assays, we show that two species of Mallophora orient to different host species and that chemical cues are produced by microorganisms. We also show that treating potential hosts with antibiotics reduces attractiveness on M. ruficauda but not to M. bigoti suggesting that endosymbiotic bacteria responsible for the host cues production should be located in different parts of the host. In fact, we were able to show that M. bigoti is attracted to frass from the most common host. Additi...

Bulletin of Entomological Research, 2017

Changes in environmental conditions influence the performance of organisms in every aspect of the... more Changes in environmental conditions influence the performance of organisms in every aspect of their life. Being capable of accurately sensing these changes allow organisms to better adapt. The detection of environmental conditions involves different sensory modalities. There are many studies on the morphology of different sensory structures but not so many studies showing their function. Here we studied the morphology of different sensory structures in the larva of a dipteran parasitoid. We occluded the putative sensory structures coupling the morphology with their function. First, we could develop a non-invasive method in which we occluded the putative sensorial structures annulling their function temporarily. Regarding their functionality, we found that larvae of Mallophora ruficauda require simultaneously of the sensilla found both in the antennae and those of the maxillary palps in order to orient to its host. When either both antennae or both maxillary palps were occluded, no o...

Zoomorphology, 2013

ABSTRACT The robber fly Mallophora ruficauda is a parasitoid of white grubs (Coleoptera: Scarabae... more ABSTRACT The robber fly Mallophora ruficauda is a parasitoid of white grubs (Coleoptera: Scarabaeidae) inhabiting in Pampa’s region of Argentina. Females locate host’s habitat and lay eggs away from the host in tall grasses. After hatching, larvae fall to the ground and actively seek hosts. Previous works suggested that female would detect the presence of host’s chemical cues, but sensory organs involved in olfaction are still unknown. However, few studies have looked at dipteran parasitoids’ sensilla and no study has been undertaken in Asilidae species. The aim of this work was to determine the presence, density, distribution and morphology of chemosensilla in M. ruficauda antennae using optic and scanning microscope techniques. We found that antennae have 4 segments: scape, pedicel, postpedicel and style. We identified basiconic and trichoidea sensilla, small and long bristles, and sensory pits. Basiconic sensilla are multiporous and are widely spread between the small bristles through the postpedicel. Tricoid sensilla are grouped in 6-8 units on latero-ventral margin of postpedicel, have mobile base, striated wall and an apical porous. Small bristles are present in the pedicel and postpedicel and long bristles are found in groups on scape and pedicel. Three different types of sensory pits were observed, with basiconic sensilla, distributed along external and internal lateral side of the postpedicel. Considering the morphological characteristics of the antennae, and based on the olfaction biomechanics, the structure and distribution of these cuticular structures of the parasitoid antennae would contribute to the odour detection mechanism in adults of M. ruficauda.

Journal of Insect Physiology, Apr 30, 2004

The robber fly Mallophora ruficauda is the most important pest of apiculture in the Pampas region... more The robber fly Mallophora ruficauda is the most important pest of apiculture in the Pampas region of Argentina. Adults prey on honeybees and other insects, while larvae parasitize larvae of scarab beetles, which live underground. Females of M. ruficauda do not search for hosts but instead lay eggs in tall pastures. Once hatched, larvae drop to the ground and burrow underground to search for their hosts. We tested in the laboratory whether larvae of M. ruficauda actively search for their hosts using host and/or host-related chemical cues. We report that M. ruficauda detects its host using chemical cues that originate in the posterior half of the host's body, most likely from an abdominal exocrine structure. This particular host-searching strategy is described for the first time in Asilidae.

The robber fly Mallophora ruficauda is one of the principal pests of apiculture in the Pampas reg... more The robber fly Mallophora ruficauda is one of the principal pests of apiculture in the Pampas region of Argentina. As adults they prey on honey bees and other insects, while as larvae they are solitary ectoparasitoids of third instar scarab beetle larvae. Females of M. ruficauda lay eggs away from the host in tall grasses. After being dispersed by the wind, larvae drop to the ground, where they dig in search of their hosts. It is known that second instar larvae of M. ruficauda exhibit active host searching behaviour towards its preferred host, third instar larva of Cyclocephala signaticollis. Although the means by which host location occurs has been studied and since superparasitism is a frequent scenario in the field, no information about host discrimination and host acceptance is available. We carried out studies in the field and behavioural experiments in the laboratory to determine if M. ruficauda is capable of quality host discrimination. We also studied if this parasitoid is c...

The robber fly Mallophora ruficauda is one of the principal apiculture pests in the Pampas region... more The robber fly Mallophora ruficauda is one of the principal apiculture pests in the Pampas region of Argentina. As adults, they prey on honeybees and other insects, while as larvae they are ectoparasitoids of third-instar scarab larvae. Females of M. ruficauda lay eggs in tall grasses. After being dispersed by the wind, larvae drop to the ground, where they dig in search of their hosts. It is known that M. ruficauda larvae exhibit active host-searching behaviour; however, it is unknown which instars are involved in this search. We carried out experiments in the laboratory to determine which larval stages are involved in host location. We report here that the second instar of M. ruficauda orientates specifically toward a source of Cyclocephala signaticollis odour, while first larval instar is indifferent to the host cues. Furthermore, we have determined that second instar larvae are more motivated to initiate exploratory movements than larva of the first stage. So far as we know, thi...

Ornitologia Neotropical, 2016

∙ The Strange‐tailed Tyrant ( Alectrurus risora ) is an insectivorous flycatcher (Tyrannidae) end... more ∙ The Strange‐tailed Tyrant ( Alectrurus risora ) is an insectivorous flycatcher (Tyrannidae) endemic to the natural tall grasslands of northern Argentina and southern Paraguay. Alectrurus risora has a polygynous mating system and the abundance of arthropods could be a major factor determining the establishment of male breeding territories and the extent of the breeding season, which is shorter than in most other reported tyrant flycatchers. To investigate this hypothesis, we examined the abundance of arthropods in upland and lowland breeding habitats. Upland habitats seem to be preferred for breeding, and usually harbour more nests. Data from one year showed that, for both grasslands, the beginning of the breeding season coincides with a greater availability of arthropods, and that the short reproductive season of A. risora coincides with a general lower availability of prey during February and March in the year we conducted the study. In upland territories, males attracted more fe...

The robber fly Mallophora ruficauda Weidemann (Diptera: Asilidae) is an important pest of apicult... more The robber fly Mallophora ruficauda Weidemann (Diptera: Asilidae) is an important pest of apiculture in the Pampas of Argentina. As adults, they prey on honey bees and other insects, whereas the larvae are ectoparasitoids of Scarabaeidae grubs. Females of M. ruficauda lay eggs in grassland where the larvae drop to the ground after being wind-dispersed and burrow underground searching for their hosts. A temporal asynchrony exists between the appearance of the parasitoid larvae and the host, with the parasitoid appearing earlier than the host. The present study investigates whether a strategy of synchronization with the host exists in M. ruficauda and determines which of the larval instars are responsible for it. Survival patterns and duration of the immature stages of the parasitoid are investigated to determine whether there is a modulation in the development at any time that could reduce the asynchrony. Experiments are carried out to determine the survival and duration of free-livi...

The robber fly Mallophora ruficauda is one of the principal pests of apiculture in the Pampas reg... more The robber fly Mallophora ruficauda is one of the principal pests of apiculture in the Pampas region of Argentina. Larvae are solitary ectoparasitoids of third-instar scarab beetle larvae. Females of M. ruficauda do not lay eggs on or near the hosts, but on tall grasses. After hatching, larvae are dispersed by the wind and drop to the ground, where they dig and search for potential hosts. It is known that second-instar larvae of M. ruficauda exhibit active host-searching behaviour towards their preferred hosts, i.e., third-instar larvae of Cyclocephala signaticollis. Although host-location seems to be mediated by chemical cues, the mechanism of orientation and the sensory organs involved in host location remain unknown. We carried out behavioural experiments in the laboratory to address these questions. We also tested whether the orientation behaviour is exclusively based on the use of chemical cues. We found that larvae of M. ruficauda detect the chemicals with chemosensilla on the...

El moscardon cazador de abejas, Mallophora ruficauda, es la plaga de la apicultura mas importante... more El moscardon cazador de abejas, Mallophora ruficauda, es la plaga de la apicultura mas importante de la region pampeana argentina. Durante el estado adulto es depredador de insectos como las abejas meliferas y durante el estado larvario es parasitoide de larvas de Scarabaeidae, comunmente denominadas gusanos blancos del suelo. El objetivo de esta Tesis es estudiar aspectos basicos de la biologia y ecologia de esta especie, con especial enfasis en los mecanismos de localizacion y explotacion de sus hospedadores. Particularmente, se estudia cual es la contribucion relativa de las hembras y de las larvas en estos procesos y como son los patrones de parasitismo resultantes. Mallophora ruficauda deposita los huevos en ootecas, las cuales son puestas en vegetacion herbacea elevada y alambrados. Las hembras regulan el numero de huevos por ooteca en funcion de la altura de oviposicion en el sustrato, depositando mas cantidad de huevos a medida que se incrementa la altura. Ademas, selecciona...